affect

¹ American  

[uh-fekt, af-ekt] / əˈfɛkt, ˈæf ɛkt /

verb (used with object)

1. to act on; produce an effect or change in.

   Cold weather affected the crops.

   Synonyms:

   alter, modify, sway, influence

2. to impress the mind or move the feelings of.

   The music affected him deeply.

   Synonyms:

   stir, touch

3. (of pain, disease, etc.) to attack or lay hold of.

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noun

1. Psychology. feeling or emotion.

2. Psychiatry. an expressed or observed emotional response.

   Restricted, flat, or blunted affect may be a symptom of mental illness, especially schizophrenia.

3. Obsolete. affection; passion; sensation; inclination; inward disposition or feeling.

affect ² American  

[uh-fekt] / əˈfɛkt /

verb (used with object)

1. to give the appearance of; pretend or feign.

   to affect knowledge of the situation.

2. to assume artificially, pretentiously, or for effect.

   to affect a Southern accent.

3. to use, wear, or adopt by preference; choose; prefer.

   the peculiar costume he affected.

4. to assume the character or attitude of.

   to affect the freethinker.

5. (of things) to tend toward habitually or naturally.

   a substance that affects colloidal form.

6. (of animals and plants) to occupy or inhabit; live in or on.

   Lions affect Africa. Moss affects the northern slopes.

7. Archaic.

   1. to have affection for; fancy.

   2. to aim at; aspire to.

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verb (used without object)

1. Obsolete. to incline, tend, or favor (usually followed byto ).

   He affects to the old ways.

affect ¹ British  

/ əˈfɛkt /

verb

1. to put on an appearance or show of; make a pretence of

   to affect ignorance

2. to imitate or assume, esp pretentiously

   to affect an accent

3. to have or use by preference

   she always affects funereal clothing

4. to adopt the character, manner, etc, of

   he was always affecting the politician

5. (of plants or animals) to live or grow in

   penguins affect an arctic climate

6. to incline naturally or habitually towards

   falling drops of liquid affect roundness

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affect ² British  

verb

1. to act upon or influence, esp in an adverse way

   damp affected the sparking plugs

2. to move or disturb emotionally or mentally

   her death affected him greatly

3. (of pain, disease, etc) to attack

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noun

1. psychol the emotion associated with an idea or set of ideas See also affection

Usage

What's the difference between affect and effect? Affect is most commonly used as a verb meaning to act on or produce a change in someone or something. Effect is most commonly used as a noun meaning a result or consequence. Remembering the difference between the words can be especially hard because these senses of the words have just about the same pronunciation. Complicating things further is the fact that affect can also be used as a noun (referring to a state of emotion, as in He had a sad affect) and effect can also be used as a verb (meaning to make happen, as in We can only effect change by taking action). However, these senses of the words are much less commonly used. You can remember that affect is most commonly used as a verb because it begins with a, for action. You can also remember how affect and effect are most commonly used by using the acronym RAVEN:R = RememberA = Affect is aV = VerbE = Effect is aN = NounHere’s an example of affect and effect used correctly in the same sentence. Example: It’s unclear what immediate effects the new law will have or how it will affect future generations. Want to learn more? Read the full breakdown of the difference between affect and effect.

Commonly Confused

Affect1 and effect, each both noun and verb, share the sense of “influence,” and because of their similarity in pronunciation are sometimes confused in writing. As a verb affect1 means “to act on” or “to move” ( His words affected the crowd so deeply that many wept ); affect2 means “to pretend” or “to assume” ( new students affecting a nonchalance they didn't feel ). The verb effect means “to bring about, accomplish”: Her administration effected radical changes. The noun effect means “result, consequence”: the serious effects of the oil spill. The noun affect1 pronounced with the stress on the first syllable, is a technical term in psychology and psychiatry. Affect2 is not used as a noun.

See affect ¹.

Related Words

See pretend.

Other Word Forms

• affectability noun
• affectable adjective
• affecter noun

Etymology

Origin of affect¹

First recorded in 1350–1400; Middle English, from Latin affectus “acted upon, subjected to; mental or emotional state” (past participle and action noun of afficere ), equivalent to af- “toward” + fec- (combining form of facere “to make, do”) + -tus action noun suffix or -tus past participle suffix; see af-

Origin of affect²

First recorded in 1400–50; late Middle English, from Middle French affecter, from Latin affectāre “to strive after, feign” (frequentative of afficere “to do to”), equivalent to af- af- + fec- ( see affect ¹) + -tāre frequentative suffix

Explanation

Affect is most often used as a verb meaning “to have an impact on,” as in “The tornado barreling towards us will affect our picnic plans.” As a verb, affect can also mean “to feign an appearance,” as in, “Don’t let that surfer’s California accent fool you. Although she affects a convincing ‘Dude, that was rad,’ she is from Minnesota and just moved out West last month.” Don’t let that affect your friendship, though, she’s probably really fun.

Example Sentences

It can change how many of these sites are available and affect how well a catalyst performs.

From Science Daily • Apr. 21, 2026

But for me to try to compete at the top level, I need to get my frustration out or else it's going to affect my performance.

From BBC • Apr. 21, 2026

Current drought conditions affect 51% of U.S. states and Puerto Rico, adding to farmer stress from high input costs.

From Barron's • Apr. 20, 2026

Autoimmune diseases can affect just about every part of the body — and tens of millions of people.

From Los Angeles Times • Apr. 20, 2026

Did it affect the body or the mind?

From "American Spirits" by Barb Rosenstock

Related Words

• alter
• change
• disturb
• influence
• interest
• involve
• touch
• upset