Word Building Secrets: Learn The Most Common English Prefixes

What is a prefix?

A prefix is a letter or group of letters added to the beginning of a word to modify its meaning. For instance, if you put “un-” in front of “happy,” it turns into “unhappy,” which means not happy. Prefixes are like small tools for changing the meaning of words.

As you review the list of prefixes, examples, and definitions on this page, be sure to note the word types associated with each.

English Vocabulary: What are Word Classes?

Word classes, also known as parts of speech, categorize words based on their function and role in sentences. Understanding word classes is crucial for constructing meaningful and grammatically correct sentences, as it helps in identifying how words interact and relate to each other within a sentence. Here’s a breakdown of the main word classes:

Nouns (n.): Words that represent people, places, things, or ideas (e.g., “dog,” “city,” “happiness”).
Example: This is a dog.

Pronouns (pron.): Words used in place of nouns to avoid repetition (e.g., “he,” “she,” “it,” “they”).
Example: She went to the store.

Verbs (v.): Words that express actions, occurrences, or states of being (e.g., “run,” “eat,” “exist”).
Example: I drink coffee every morning.

Adjectives (adj.): Words that describe or modify nouns or pronouns, often by indicating quality, quantity, or possession (e.g., “big,” “beautiful,” “my”).
Example: This is a beautiful car.

Adverbs (adv.): Words that modify verbs, adjectives, or other adverbs, typically by indicating manner, place, time, frequency, degree, or certainty (e.g., “quickly,” “here,” “often”).
Example: He was walking slowly.

Prepositions (prep.): Words that show relationships between other words in a sentence, often indicating direction, location, or time (e.g., “in,” “on,” “at,” “between”).
Example: The cat is under the table.

Conjunctions (conj.): Words that connect words, phrases, or clauses (e.g., “and,” “but,” “or”).
Example: She wanted to go, but it was raining.

Interjections (interj.): Words or phrases that express strong emotions or reactions (e.g., “wow,” “oh,” “hey”).
Example: Wow, that’s amazing!

English Vocabulary: How To Use Prefixes

Express Your Ideas More Accurately

Let’s take a look at how word building with prefixes can help you.

Start with simple sentences:

This is a big dog.
This dog is very happy.
This dog can jump easily.

After reviewing the vocabulary list on this page, you should be able to replace any verbs, nouns, adjectives, and adverbs in your sentences with their counterparts from this list. Even if the new sentences are not meaningful or don’t make sense contextually, they will still be grammatically correct.

For example:

This is an unhappy dog.
This dog is very cooperative.
This dog can interact with humans comfortably.

You can step-by-step replace the words and easily form sentences that sound relatively complex.

Consider this sentence:

Carl Jung’s books are very nice.
Jung’s work helps us demystify human behavior.
Jung’s contributions undoubtedly deserve being an integral part of every psychology department‘s curriculum.

Understand the Meaning of New Words

Understanding new English words involves breaking them down into their components to grasp their meanings. By examining prefixes, roots, and suffixes, you can deduce the meaning of complex words. This approach helps not only in memorizing vocabulary but also in applying the words accurately in different contexts. Let’s look at a few examples:

Example 1: Biodegradable (adj.)

Take a word like biodegradable for instance. Majority of students will consider it a difficult a word and many will fail to define it properly. However, if I ask them about “grade” they will almost always provide the correct definition, and synonyms. Biodegradable is:

Bio- (life, living, related to living things)
de- (reversal, removal, moving down, moving away, separation)
grade (step, stage, level)
-able (can be)

Knowing that, you can easily conclude that degrade is similar to breaking down in this context. While talking about people, it can have the same meaning as “looking down” on a person or a group. Biodegradable is something that can be broken down by living organisms.

Example 2: Decomposition (n.)

Just like how we literally degraded “biodegradable” (see what I did there?), we can decompose “decomposition” like this:

de- (undo, reversal, removal, moving down, moving away, separation)
co- (together, joint, with)
pose (place, position)
-tion (this just makes it a noun)

Composition is when things are placed together. So, “decomposition” literally means taking them apart, it is the process of breaking down or disintegrating something into simpler parts or elements.

Example 3: Propulsion, Propeller (n.)

Propulsion:

pro- (forward, in favor of)
pulse (drive, push)
-ion (suffix indicating an action or process)

“Propulsion” refers to the action or process of driving or pushing something forward, typically referring to the force that moves an object or vehicle through air, water, or space. It encompasses various methods of generating thrust or propulsion, such as jet engines, rockets, or propellers.

Propeller:

pro- (forward, in favor of)
pel (drive, push)
-er (suffix indicating a person or thing that performs an action)

So, “propeller” essentially means a device that pushes or drives something forward. It typically refers to the rotating blades of an aircraft or boat that generate thrust to propel the vehicle through air or water.

Example 4: Compartmentalization (n.)

com- (together, joint, with)
part (portion, division)
-ment (state, condition, act of)
-al (forming an adjective)
-ize (to make, to cause to become)
-tion (forming a noun)

First, “com-” suggests bringing things together, followed by “part,” indicating division or portion. “-al” makes it an adjective and then the suffix “-ize” transforms compartmental into a verb, making it “compartmentalize,” which means to create compartments or divisions. Finally, “-tion” turns it into a noun, resulting in “compartmentalization,” referring to the process of organizing or dividing into distinct sections.

Complete List of Prefixes in English

Co-

Co-: Meaning “together” or “joint”

Compose (v.): To form by putting together different parts; to create or make up.
For a list of common English roots like “pose”, visit this page.
Coexist (v.): To exist at the same time or in the same place.
Cooperate (v.): To act jointly with others for a common purpose or benefit.
Coordinate (v.): To bring different elements into a harmonious or efficient relationship.
Coordinator (n.): A person responsible for organizing and synchronizing the activities of others to ensure efficiency and effectiveness.
Collaborate (v.): To work together on an activity or project, especially to produce or create something.
Collaboration (n.): The act of working together with others to achieve a common goal or objective.
Coauthor (n.): A person who collaborates with another in writing a book, article, or other literary work.
Copilot (n.): A second pilot in an aircraft who assists or relieves the captain.
Colleague (n.): A person who works with others in the same profession, organization, or academic institution. They are typically seen as peers or associates with whom one collaborates or interacts professionally.

Pre-

Pre-: The prefix “pre-” means “before” or “prior to.” It is commonly used to indicate something that comes before another thing in time, place, or order. For example, in the word “preview,” “pre-” indicates that it is a viewing that comes before the actual event.

Preview (v., n.): As a verb, “preview” means to view or examine something in advance, typically before it is officially released or presented to others.
As a noun, “preview” refers to a preliminary showing or examination of something, such as a film, event, or product, before it is made available to the public.
Prefix (n.): A word, letter, or number placed before another.
Predict (v.): To say or estimate that (a specified thing) will happen in the future or will be a consequence of something.
For a list of common English roots like “dict”, visit this page.
Prepare (v.): To make (something) ready for use or consideration.
Prescribe (v.): To advise and authorize the use of (a medicine or treatment) for someone, especially in writing.
For a list of common English roots like “scribe”, visit this page.
Preserve (v.): To maintain (something) in its original or existing state.

By adding the suffix -tion, you can turn these verbs into nouns: prediction, preparation, prescription, preservation. For a list of common English suffixes, visit this page.

Pro-

Pro-: The prefix “pro-” can mean “before” or “forward” in certain contexts, indicating something that comes before or precedes in time, place, or order. Here are a few examples:

Prospect (n.): A person or thing considered likely to succeed or be successful in the future; a potential candidate or opportunity. In a more literal sense, it can also refer to a view or scene, especially one that is pleasing or picturesque.
To learn more about the root “spect”, click here.
Project (n.): A planned endeavor or undertaking, often involving research, design, or construction, with specific goals and objectives. It can also refer to a temporary task or assignment with a defined scope and timeline.
Promote (v.): To support or advance the progress or growth of something, such as a cause, idea, product, or person, often by advocating for or actively encouraging its development or success.
Promotion (n.): The act of promoting or advancing something, typically involving efforts to increase awareness, visibility, sales, or status. It can also refer to the advancement of an employee to a higher rank or position within an organization.

These words share the common theme of indicating a forward movement or progression, whether it’s in terms of potential success (prospect), planned endeavors (project), advancement (promote), or efforts to increase visibility or status (promotion). Prefix “pro-” can also mean “in favor of”. Scroll down further for that.

De-

De-: The prefix “de-” can indicate reversal or removal, imply movement down or away, denote removal or separation, and signify negation or reversal in words like “deactivate,” “descend,” “detach,” and “declassify”.

Decrease (v.): To make or become smaller or fewer in size, amount, intensity, or degree.
Depart (v.): To leave, typically in order to start a journey.
Department (n.): A division (or a part!) of a large organization such as a government, university, business, or shop dealing with a specific area of activity.
Deflate (v.): To let air or gas out of (a tire, balloon, or similar object); to reduce or cause to contract.
Dethrone (v.): To remove (a ruler or leader) from power or authority. Throne is the seat kings sit on. Dethroning a king would mean to take that seat (power) away from them.
Detour (n.): A long or roundabout route taken to avoid something or to visit somewhere along the way.
Deactivate (v.): To make (something, typically a device or system) inactive by disconnecting or switching off its power supply.
Descend (v., n.): To move or fall downward; An act of moving downward, dropping, or falling.
Detach (v.): To separate or disconnect (something) from something else, typically with an abrupt pulling action.
Declassify (v.): To remove the classification from (information, documents, etc.) so that it may be freely available to the public.
Demystify (v.): To make something easier to understand or explain, especially something that was previously perceived as mysterious or complex. (mystery, mystify)

In-

In-: The prefix “in-” indicates negation or absence; without.

Inefficient (adj.): Not achieving maximum productivity; wasteful or ineffective.
Incomplete (adj.): Not having all the necessary parts or elements; unfinished.
Inaccurate (adj.): Not correct or precise; containing errors.
Inadequate (adj.): Lacking the quality or quantity required; insufficient.
Incapable (adj.): Unable to do or achieve something; lacking the necessary ability or strength.
Indirect (adj.): Not directly caused by or resulting from something; not straightforward.
Insecure (adj.): Not confident or assured; uncertain or anxious about oneself or something.
Insecurity (n.): A feeling of uncertainty or self-doubt about oneself or one’s abilities.
Inequality (n.): Lack of equality or fairness; disparity.
Injustice (n.): Lack of fairness or justice; unfair treatment.
Inject (v.): Introduce a substance, typically a liquid or a drug, into a person or an organism, usually using a syringe or a similar device.

Different Meanings of "In-"

Note: the prefix “in-” can also imply into, inside, or within.

Import (v.): To bring goods or services into a country from abroad for sale or use.
Import (n.): A product or service brought into a country from abroad, typically for sale or trade.
For a list of common English roots like “port”, visit this page.
Internal (adj.): Relating to the inside or inner part; situated or occurring within.
Internal (n.): An inner part or component, especially of an organization or structure.
Infiltrate (v.): To enter or gain access to (an organization, place, etc.) gradually and often secretly, especially in order to acquire secret information or exert influence.
Ingest (v.): To take food, drink, or another substance into the body by swallowing or absorbing it.
Integrate (v.): To combine (one thing) with another so that they become a whole.
Inflate (v.): To fill a balloon, tire, or a similar object with air or gas. To increase or raise (something) by a large or excessive amount.

Different Forms of "In-"

Note: the prefix “in-” can change to “il-” before words starting with “L,” “im-” before words starting with “M” or “P”, and “ir-” before words starting with “R”.

Illegal: Contrary to or forbidden by law; unlawful.
Immature: Not fully developed or grown; not mature.
Impossible: Not able to occur, exist, or be done; not possible.
Irregular: Not following a regular pattern; not conforming to established rules or norms.

Sub-

Sub-: The prefix “sub-” implies something that is under, below, or beneath something else, both physically and metaphorically. It can also suggest nearness, partiality, or being secondary in nature.

Submarine (n.): A watercraft designed to operate underwater, typically used for military purposes.
Subconscious (adj.): Existing or occurring in the mind without one’s full awareness.
Substandard (adj.): Below the usual or required standard.
Subordinate (n., adj.): A person under the authority or control of another; lower in rank or position.
Submerge (v.): To put or sink below the surface of water or another liquid.
Subterranean (adj.): Existing, occurring, or done beneath the earth’s surface.
Subdue (v.): To overcome, quieten, or bring under control.
Subatomic (adj.): Relating to particles that are smaller than an atom, such as protons, neutrons, and electrons.
Subside (v.): To become less intense, violent, or severe; to decrease gradually.
Subsidiary (n., adj.): A company controlled by a holding company; serving to assist or supplement.
Subsidize (v.): To support financially or provide assistance to.

Inter-

Inter-: The prefix “inter-” denotes a sense of “between” or “among,” suggesting interaction, connection, or relationship between different entities, locations, or groups. It often implies a mutual exchange, communication, or influence occurring across boundaries or within a collective context.

Interact (v.): To communicate or engage with someone or something in a reciprocal or mutual manner.
Interfere (v.): To intervene in a situation or process, typically in a way that hinders or obstructs its progress.
Interlock (v.): To connect or engage two or more things firmly or closely together.
Interpose (v.): To place or insert something between other things, often to intervene in a conversation or discussion.
Intercede (v.): To act or interpose on behalf of someone in difficulty or trouble, especially by pleading or petitioning.
Interject (v.): To interrupt a conversation or discourse with a comment, remark, or question.
Intertwined (adj.): Two or more things closely connected or twisted together, often making it difficult to separate them. It suggests a complex and intricate relationship between the entities involved.

Ad-

Ad-: The prefix “ad-” originates from Latin, where it often signifies “toward” or “in the direction of.” In English, it is commonly used to form words that convey the idea of motion, progression, or orientation towards something. Additionally, “ad-” can imply a sense of attachment, addition, or adherence to a particular concept or action.

Adhere (v.): To stick or cling to something.
Adherence (n.): The act of sticking or clinging to something, especially a belief, principle, or course of action.
Adapt (v.): To make suitable adjustments or modifications.
Adaptation (n.): The process of making suitable adjustments or modifications to fit changing circumstances or conditions.
Advance (v.): To move forward or make progress.
Advancement (n.): Progress or improvement, especially in terms of social, professional, or academic status.
Address (v.): To speak to someone or direct attention to something.
Admit (v.): To allow entry or confess to something.
Admission (n.): The act of granting permission to enter or access a place or institution; also, the process of acknowledging or confessing to something, often an error or wrongdoing.
Adjust (v.): To alter or change in order to fit or accommodate.
Adjustment (n.): A change or modification made to achieve better fit, function, or compatibility with a particular situation or environment.
Advertise (v.): To promote or make known to the public.
Advertisement (n.): A public notice or announcement intended to promote a product, service, or event.
Advocate (v.): To support or recommend a particular cause or policy.
Addict (n.): A person who is dependent on a particular substance or activity.
Addiction (n.): A state of dependency on a particular substance or activity, characterized by compulsive behavior and adverse effects on one’s physical and mental health.
Administer (v.): To manage or supervise the execution of something.
Administration (n.): The management or supervision of the execution of laws, policies, or organizational tasks.
Adventure (n.): An exciting or unusual experience.
Adventure (v.): To engage in an exciting or risky activity.

Mono-, Bi-, Tri-, Cent-, Milli-

Mono-: Meaning “one” or “once”
Bi-: Meaning “two” or “twice”
Tri-: Meaning “three” or “thrice”
Cent-: 100
Milli-: 1000

Bicycle (n.): An object with two wheels
Tricycle (n.): An object with three wheels
Bipolar (adj.): Something having or involving two poles or extremities.
Monopod: A support or stand with a single leg or projection.
Bipod: A support or stand with two legs or projections.
Tripod: A support or stand with three legs or projections.
iPod: Nah, just kidding.
Biped (n.), Bipedal (adj.): Two-legged creature or animal.
Centipede (n.): A creature with a hundred legs.
Millipede (n.): A creature with a thousand legs.
Century (n.): 100 years
Millennium (n.): 1000 years
Centimeter (n.): 1/100 of a meter
Millimeter (n.): 1/1000 of a meter
Percent (n.): In a hundred

Contra-, Counter-

Contra-, Counter-: The prefixes “contra-” and “counter-” both imply opposition, contrast, or acting in an opposite direction. They are used to indicate something against or contrary to a particular concept or action.

Contradict (v.): To assert or express the opposite of a statement or belief, often in disagreement with it. It involves stating or suggesting something that is contrary to what has been previously stated or believed.
For a list of common English roots like “dict”, visit this page.
Contradictory (adj.): Expressing or implying the opposite of what has been stated; inconsistent or conflicting.
Counteract (v.): To act in opposition to something; to neutralize or hinder the effects of.
Contravene (v.): To violate or act against a law, rule, or principle.
Counterbalance (n., v.): A weight or force that balances or opposes another; to offset the effect of something with an equal force.
Contrary (adj., n.): Opposite in nature, direction, or meaning; a fact or statement that is opposite to another.
Counterargument (n.): An argument or viewpoint presented in opposition to another argument.
Counterproductive (adj.): Having the opposite of the desired effect; tending to hinder rather than promote progress or success.
Contrarian (n., adj.): A person who opposes or rejects popular opinion or prevailing trends; characterized by opposition to prevailing beliefs or practices.
Counteroffensive (n., adj.): A military action launched in response to an enemy’s attack; characterized by aggressive defensive action.
Counterattack (n.): An offensive action taken in response to an attack, especially in warfare or sports.
Counterstrike (v., n.): As a verb, “counterstrike” means to launch a swift and aggressive response or attack in retaliation to an opponent’s action or attack. As a noun, “counterstrike” refers to the act of launching such a response or attack.

Bio-

Bio-: The prefix “bio-” is derived from the Greek word “bios”, meaning “life”. In English, “bio-” is used as a prefix to form words related to living organisms, biology, or the study of life.

Biography (n.): An account of someone’s life written by someone else.
Biome (n.): A large naturally occurring community of flora and fauna occupying a major habitat.
Bioluminescence (n.): The production and emission of light by a living organism.
Biopsy (n.): The removal and examination of tissue from a living body to diagnose or investigate a disease.
Biodegradable (adj.): Capable of being decomposed by bacteria or other living organisms.
Biosphere (n.): The regions of the surface, atmosphere, and hydrosphere of the earth occupied by living organisms.
Biotechnology (n.): The exploitation of biological processes for industrial and other purposes, especially the genetic manipulation of microorganisms for the production of antibiotics, hormones, etc.
Biomechanics (n.): The study of the mechanical laws relating to the movement or structure of living organisms.
Biosynthesis (n.): The production of complex molecules within living organisms or cells.
Biocatalyst (n.): A substance, typically an enzyme, that speeds up a chemical reaction in a living organism.

Hydro-

Hydro-: The “hydro-” prefix primarily signifies a connection to water. It originates from the Greek word “hydor”, meaning water.

Hydrate (v.): To supply or combine with water, restoring moisture or fluid to something.
Hydrolectric (adj.): Relating to the generation of electricity from water power.
Hydroplane (n.): A light, fast motorboat designed to skim over the surface of water.
Hydroponics (n.): A method of growing plants without soil, using mineral nutrient solutions in a water solvent.
Hydrotherapy (n.): The use of water in the treatment of various conditions, such as physical injuries or mental stress.
Hydrophobia (n.): An extreme or irrational fear of water.
Hydrophobic (adj.): Repelling or failing to mix with water.

Syn-

Syn-: It is derived from the Greek word “syn”, meaning “with” or “together”. In English, “syn-” is used to indicate association, convergence, or similarity.

Synonym (n.): A word or phrase that means the same or nearly the same as another word or phrase in the same language.
Synergy (n.): The interaction or cooperation of two or more organizations, substances, or other agents to produce a combined effect greater than the sum of their separate effects.
Synthesize (v.): To combine or form (a complex whole) by the combination of simpler elements or parts.
Syndicate (n.): A group of individuals or organizations combined to promote some common interest.
Synchronize (v.): To cause to occur or operate at the same time or rate.
Syntax (n.): The arrangement of words and phrases to create well-formed sentences in a language.
Syndrome (n.): A group of symptoms that consistently occur together or a condition characterized by a set of associated symptoms.
Synchronous (adj.): Occurring, existing, or done at the same time or in unison.

Di-

Di-: The prefix “di-” means “two,” “double,” or “twice.” It is often used to describe something that is split into two parts or involves two elements. It can also mean “apart” or “in different directions” to refer to turning aside or changing direction rather than dividing into two parts.

Dialogue (n.): A conversation between two or more people.
Divide (v.): To separate or split into two or more parts.
Division (n.): The act of separating something into parts or the process of being separated.
Dilemma (n.): A situation requiring a choice between two equally undesirable options.
Dichotomy (n.): A division into two sharply contrasting parts or things.
Dioxide (n.): A molecule containing two oxygen atoms.
Diverge (v.): To move or extend in different directions from a common point.
Divert (v.): To change the direction or course of something.

A-

A-: The prefix “a-” is commonly used to indicate absence, lack, negation, or reversal of the base word’s meaning.

Atheist (n.): A person who lacks belief in the existence of gods or deities.
Achromatic (adj.): Lacking color; having no hue.
Atypical (adj.): Not representative of a type, group, or class; unusual or abnormal.
Apathy (n.): Lack of interest, enthusiasm, or concern; indifference.
Asymmetrical (adj.): Not having symmetry; lacking balanced proportions.
Amoral (adj.): Lacking moral principles; without regard for right or wrong.
Anarchy (n.): Absence of government or authority; chaos or disorder.
Aseptic (adj.): Free from contamination by harmful bacteria, viruses, or other microorganisms.
Agnostic (n.): A person who believes that the existence of gods or the divine is unknown or unknowable.

Dis-

Dis-: The prefix “dis-” typically denotes negation, reversal, or separation. It is commonly used to indicate the opposite or absence of something. For example, in the word “disagree,” “dis-” indicates the opposite of agreement.

Disagree (v.): Not agree
Disappear (v.): Not appear
Dislike (v.): Not like
Disadvantage (n.): A condition or circumstance that puts someone in an unfavorable or inferior position.
Disagreement (n.): A lack of consensus or harmony in opinion or belief.
Disapproval (n.): The act of expressing a negative judgment or disfavor towards something.
Disabled (adj.): Having a physical, mental, or cognitive impairment that substantially limits one or more major life activities.

Mis-

Mis-: The prefix “mis-” means wrongly or incorrectly. It is used to indicate a negative or opposite meaning to the root word. For example, in the word “misunderstand,” “mis-” indicates a failure to understand correctly.

Misunderstand (v.): To understand wrongly
Misbehave (v.): To behave badly
Mistranslate (v.): To translate wrongly
Mistake (v.): To make an error or to do something incorrectly.
Misspeak (v.): To speak incorrectly or inaccurately. To make a mistake while speaking.
Mispronounce (v.): To pronounce wrongly
Miscommunication (n.): A failure to communicate clearly or effectively.
Mismanagement (n.): Poor or ineffective management of resources or affairs.
Misconception (n.): A mistaken or incorrect belief or understanding.
Misaligned (adj.): Not properly aligned or positioned.
Misbehaved (adj.): Behaving badly or inappropriately.
Misjudged (adj.): Incorrectly assessed or evaluated.
Mistakenly (adv.): In a way that is based on a misunderstanding or error.
Mischievously (adv.): In a playful or teasing manner that is likely to cause trouble or annoyance.
Misguidedly (adv.): Based on mistaken judgment or understanding.

Tele-

Tele-: The prefix “tele-” refers to distance or far, often associated with communication over long distances. It is derived from the Greek word “tele”, meaning “far off” or “distant”.

Teleport (v.): To instantaneously transport or transmit an object or person to a distant location.
Teleportation (n.): The act or process of instantaneously moving or transmitting an object or person from one place to another.
Telepathy (n.): The supposed communication of thoughts or ideas between minds without the use of conventional senses.
Telescope (n.): An optical instrument used for viewing distant objects, typically consisting of a tube with lenses or mirrors.
Television (n.): A system for transmitting visual images and sound over a distance, used for entertainment, education, news, etc.
Telephone (n.): A telecommunications device used for voice communication over long distances.
Telegraph (n.): A system for transmitting messages over long distances using coded signals.
Telegram (n.): A message sent by telegraph, typically in the form of a printed piece of paper.

En-

En-: The prefix “en-” typically means to make something into or to cause a state of being.

Enable (v.): To make something possible or capable of happening.
Enrich (v.): To improve the quality or value of something.
Enlarge (v.): To make something larger or to increase in size.
Encourage (v.): To inspire or give support (and courage) to someone to do something.
Endanger (v.): To put something or someone at risk or in peril.
Encase (v.): To cover or surround something completely.
Envision (v.): To imagine or picture something in the mind.
Engulf (v.): To completely surround or cover something.
Entangle (v.): To become twisted or caught in something.

Re-

Re-: The prefix “re-” means again or back. It is used to indicate repetition or restoration of the action expressed by the root word. For example, in the word “redo,” “re-” indicates the action of doing something again.

Rewrite (v.): To write again
Return (v.): To go back
Rebuild (v.): To build again
Reform (v., n.): To make changes in something, typically in order to improve it; the action or process of reforming.
Rebirth (n.): The process of being born again or brought back to life; a revival or renewal.
Reusable (adj.): Able to be used again multiple times, typically after being cleaned or reset.
Recyclable (adj.): Capable of being recycled or reused in some way, typically to create new products or materials.
Reversible (adj.): Capable of being turned around, flipped, or changed to the opposite direction or state.

Un-

Un-: The prefix “un-” is used to indicate the reversal or negation of the action expressed by the root word. It is commonly used to form words with the opposite meaning of the original word. For example, in the word “undo,” “un-” indicates the reversal of the action of doing.

Unhappy (adj.): Not happy
Unfair (adj.): Not fair
Uncommon (adj.): Not common
Undo (v.): To reverse or cancel the effects or actions of something previously done.
Unmask (v.): To reveal the true nature or identity of something or someone that was previously hidden or disguised.
Uncomfortably (adv.): In a way that causes physical or mental discomfort or unease.

Poly-

Poly-: The prefix “poly-” comes from the Greek word “polys”, meaning “many” or “much”. In English, it is used to form words that indicate the presence of many or much of something, or the involvement of multiple elements or aspects.

Polygon (n.): A plane figure with at least three straight sides and angles.
Polytheism (n.): The belief in or worship of more than one god.
Polyclinic (n.): A clinic offering treatment in many branches of medicine.
Polyglot (n.): A person who knows and is able to use several languages.
Polymer (n.): A substance that has a molecular structure consisting chiefly or entirely of a large number of similar units bonded together.
Polytechnic (n.): A college offering instruction in many industrial arts and applied sciences.
Polyamory (n.): The practice of engaging in multiple romantic or sexual relationships with the consent of all parties involved. A form of degeneracy.

Ex-

Ex-: The prefix “ex-” can be used to indicate something that was once part of a group but is now outside of it or has left it. It can also imply a former status or position. For example, in the word “ex-president,” “ex-” indicates that the individual was once a president but no longer holds that position. Similarly, in “ex-boyfriend” or “ex-girlfriend,” it signifies someone who was formerly in a romantic relationship with the speaker but is no longer.

Ex-boyfriend
Ex-girlfriend
Ex-husband
Ex-wife
Ex-president
Ex-employee
Ex-partner
Ex-student
Ex-member
Ex-convict

Different Meanings of "Ex-"

Ex-: The prefix “ex-” can also signify “out” or “outside.” It is often used to denote something that is outside of or beyond a particular boundary, contrasting with the prefix “in-” which implies being within or inside. For instance, “external” refers to something outside or beyond, while “internal” suggests something within or inside.

Exterior (adj., n.): Referring to the outer surface or appearance of something; the outer part or surface. Opposite of interior.
Exclude (v.): To prevent someone or something from being included or considered. Opposite of include.
Exclusion (n.): The act or process of excluding or the state of being excluded. Opposite of inclusion.
Exclusive (adj.): Limited to only one person or group; not including others. Opposite of inclusive.
Exhale (v.): To breathe out air or vapor from the lungs. Opposite of inhale.
Extract (v., n.): To remove or take out, especially by force or effort; a substance obtained by extracting.
External (adj.): Relating to, located on, or dealing with the outside or outer part of something. Opposite of internal.

Pro-, Anti-

Pro-, Anti-: The prefix “pro-” typically means “in favor of” or “in support of”, while the prefix “anti-” means “against” or “opposed to”.

Pro-war vs. anti-war
Probiotics vs. antibiotics
Pro-vaccine vs. anti-vaccine
Pro-abortion vs. anti-abortion
Pro-immigration vs. anti-immigration
Pro-environment vs. anti-environmental
Pro-capitalism vs. anti-capitalism

Semi-

Semi-: The prefix “semi-” means “half” or “partly” and is used to indicate something that is partial, incomplete, or halfway in nature.

Semiformal (adjective): Referring to a level of formality that is less than formal but more than casual.
Semiconscious (adjective): Partly conscious; not fully awake or aware.
Semiautomatic (adjective): Partially automatic; requiring some manual operation.
Semifinal (noun): A game or contest held to determine which competitors will advance to the final round.
Semidetached (adjective): Describing a house that is joined to another on one side, sharing a common wall.
Semiaquatic (adjective): Referring to organisms that live both on land and in water, or that are adapted to living in both environments.

Note: when “semi” is hyphenated in compound words, it is pronounced as “sem-eye”. When it’s not hyphenated, it’s typically pronounced as “sem-ee”.

Multi-

Multi-: Commonly used in English to denote the presence of multiple or many instances of something. When attached to a word, “multi-” conveys the idea of abundance, variety, or involvement of numerous elements.

Multitask (v.): To perform multiple tasks simultaneously or alternately.
Multinational (adj.): Relating to or involving several nations.
Multitude (n.): A large number of people or things.
Multiply (v.): To increase or cause to increase greatly in number or quantity.
Multifaceted (adj.): Having many facets or aspects.
Multimedia (n.): The combined use of several media, such as sound, video, and text.

Note: when “multi” is hyphenated as a prefix in compound words, such as “multi-ethnic”, it is pronounced as “mul-tie”. However, when “multi” stands alone or is part of a word without a hyphen, like “multicultural”, it is pronounced as “mul-tee”.

Post-

Post-: The prefix “post-” means “after” or “later.” It is often used to denote something that occurs after a specified time or event.

Postpone (v.): To delay an event or action until a later time.
For a list of common English roots like “pone”, visit this page.
Postwar (adj.): Relating to or occurring after a war has ended.
Postgraduate (n., adj.): A student who has completed a bachelor’s degree and is pursuing further education, or relating to such education.
Postscript (n.): Additional information added at the end of a letter after the signature.
Postmortem (n., adj.): An examination of a dead body to determine the cause of death; occurring after death.
Postnatal (adj.): Relating to the period immediately after childbirth.
Posthumous (adj.): Occurring or published after the death of the originator.
Posterior (adj., n.): Situated behind or at the rear; coming after in time or order.
Postprocessing (n.): Series of operations or adjustments performed on a digital image, document, or data after the initial processing stage. It typically involves refining, enhancing, or finalizing the output to achieve desired results or improve quality.

Trans-

Trans-: The prefix “trans-” originates from Latin and carries the meaning of “across,” “beyond,” or “through.” It denotes movement or change from one state or place to another. It implies a sense of crossing boundaries or traversing through something. In essence, words with the prefix “trans-” often involve transitions, transfers, or transcending from one condition to another.

Transport (v., n.): Relates to moving people or goods from one place to another, usually by vehicles or conveyance systems.
For a list of common English roots like “port”, visit this page.
Translate (v.): Means converting text or speech from one language to another for understanding across different linguistic contexts.
Transatlantic (adj.): Relating to or situated on the other side of the Atlantic Ocean.
Transcend (v.): To go beyond the limits of; to surpass or exceed.
Transcontinental (adj.): Extending or relating to a passage or route across two or more continents.
Transcribe (v.): To make a written or typed copy of dictated or recorded material.
Transfer (v.): To move from one place to another; to convey or transport.
Transition (n.): The process or period of changing from one state or condition to another.
Transmit (v.): To send or convey from one person or place to another.
Transfigure (v.): To transform or change in form, appearance, or nature, especially in a magical or mysterious way.
Transient (adj.): Lasting only for a short time; temporary or impermanent.

Auto-

Auto-: The prefix auto- comes from the Greek word “autos,” meaning “self” or “by itself.” It is used to denote that something operates independently or automatically, without external control or assistance.

Autograph (n.): A person’s signature written by themselves.
Automobile (n.): A self-propelled vehicle designed for transportation, such as a car or truck.
Automatic (adj.): Designed to operate or function on its own without manual control.
Autonomy (n.): The state of having self-governance or independence.
Autonomous (adj.): Describing something or someone that operates independently.
Autonomously (adv.): Acting in a manner that demonstrates self-governance or independence.
Autonomic (adj.): Relating to the autonomic nervous system.
Autocrat (n.): A ruler who has absolute power.
Autofill (v.): A feature in software that automatically fills in fields based on previous entries.

Uni-

Uni-: The prefix “uni-” originates from the Latin word “unus,” meaning “one” or “single.” It is used to denote singularity or unity in various contexts.

Unite (v.): To come or bring together for a common purpose.
Unify (v.): To make or become united, uniform, or whole.
United (adj.): Joined together for a common purpose.
Unity (n.): The state of being united.
Unicycle (n.): A vehicle with a single wheel.
Unilateral (adj.): Involving only one side.
Unidirectional (adj.): Moving in one direction only.
Unison (n.): Simultaneous performance of action.
Unipolar (adj.): Relating to a single pole or kind of polarity.
Uniform (n., adj.): Special clothing worn by a group; remaining the same in all cases.
Universe (n.): All existing matter, space, time, energy, and the physical laws binding them.

Pseudo-

Pseudo-: The prefix “pseudo-” is derived from the Greek word “pseudes,” meaning “false” or “deceitful.” It indicates something that is false, deceptive, or not genuine.

Pseudonym (n.): A false name used by an author instead of their real name.
Pseudoscience (n.): A belief or practice presented as scientific but lacking empirical evidence.
Pseudo-intellectual (n.): Someone who pretends to be more intelligent than they are.

Over-, Under-

Over-, Under-: “Over-” denotes an excess, while “under-” indicates a deficiency. They are used with verbs and describe amounts in relation to something.

Overcook, Undercook (v.): Cooking for too long or not enough, respectively.
Oversleep, Undersleep (v.): Sleeping too much or too little.
Overwater (v.): To provide with excess water.
Overestimate (v.): To judge something as greater than it is.
Underestimate (v.): To judge something as smaller than it is.
Overwhelm (v.): To bury or drown beneath a huge mass.
Underwhelm (v.): To fail to impress due to lack of impact.

Fore-

Fore-: The prefix “fore” typically refers to the front part of something, often used in contexts related to direction or position. It can also denote something that comes before or precedes in time or order.

Foresee (v.): To be aware of beforehand; anticipate or predict.
Forecast (n.): A prediction or estimate of future events, especially weather conditions.
Forewarn (v.): To warn (someone) in advance of a possible danger, problem, or other unpleasant situation.
Forefather (n.): An ancestor, especially a male ancestor.
Forefront (n.): The leading or most important position or place.
Forecourt (n.): The area in front of a building, typically used as a driveway or entrance space.
Forebode (v.): To be a warning or indication of (a future event).
Foremost (adj.): Most prominent in rank, importance, or position.
Foreclosure (n.): The action of taking possession of a mortgaged property when the mortgagor fails to keep up their mortgage payments.

Infra-, Ultra-

Infra-, Ultra-: The prefix “infra-” typically denotes something that is below or beneath. It suggests being in a position or condition that is lower in level, position, or value compared to something else. The prefix “ultra-” generally signifies something that is beyond or exceeding the usual limits, standards, or expectations.

Infrastructure: Basic structures like roads and bridges.
Infrared: Heat radiation beyond red light.
Ultraviolet: Light rays beyond violet.
Infrasound: Sound waves below human hearing.
Ultrasonic: Sound waves too high for humans to hear.

Op-

Op-: The prefix “op” usually indicates “against” or “towards” in various contexts.

Oppress (v.): To keep someone in subservience and hardship, especially by unjust exercise of authority.
Oppression (n.): Prolonged cruel or unjust treatment or control by authority.
Opponent (n.): Someone who competes against or opposes another in a contest, game, or argument.
Oppose (v.): To actively resist or refuse to comply with a person, group, or idea.
Opposite (adj.): Situated on the other or further side when seen or considered from a specified or implicit viewpoint; facing.

Para-

Para-: The prefix “para-” often denotes a relationship of beside, alongside, or beyond.

Paradigm (n.): Represents a model or pattern that stands beside or beyond other examples.
Paralegal (n.): Works alongside or in a position beside lawyers.
Parachute (n.): Acts beside or beyond the falling object, providing support and safety.
Paradox (n.): Presents a statement that stands beside or beyond typical logical expectations, often appearing contradictory.
Paragon (n.): Represents a model of excellence that stands beside or beyond others.
Parasite (n.): Lives beside or beyond its host organism, often at the host’s expense.
Paralysis (n.): Refers to a condition where movement is hindered or stands beside or beyond the norm due to injury or illness.
Paramedic (n.): Provides medical care beside or beyond the capabilities of basic first aid.
Paraphrase (v.): Expresses meaning in a different way beside or beyond the original wording.
Paranoia (n.): Involves irrational beliefs or thoughts that stand beside or beyond typical perceptions of reality.

While the meanings of these words vary widely, they all contain the notion of something being beside or beyond, either physically, logically, or metaphorically. This common thread ties them together under the prefix “para-“.

List of Prefixes (Alphabetical)

A-
Ad-
Anti-
Auto-
Bi-
Bio-
Cent-
Co-
Contra-
Counter-
De-
Di-
Dis-

En-
Ex- (former)
Ex- (out)
Fore-
Hydro-
In-
Infra-
Inter-
Milli-
Mis-
Mono-
Multi-
Op-

Over-
Para-
Poly-
Post-
Pre-
Pro- (before)
Pro- (in favor of)
Pseudo-
Re-
Semi-
Sub-
Syn-
Tele-

Trans-
Tri-
Un-
Uni-
Ultra-
Under-

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