affect
1 Americanverb (used with object)
noun
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affects
plural
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Psychology. feeling or emotion.
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Psychiatry. an expressed or observed emotional response.
Restricted, flat, or blunted affect may be a symptom of mental illness, especially schizophrenia.
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Obsolete. affection; passion; sensation; inclination; inward disposition or feeling.
verb (used with object)
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to give the appearance of; pretend or feign.
to affect knowledge of the situation.
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to assume artificially, pretentiously, or for effect.
to affect a Southern accent.
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to use, wear, or adopt by preference; choose; prefer.
the peculiar costume he affected.
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to assume the character or attitude of.
to affect the freethinker.
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(of things) to tend toward habitually or naturally.
a substance that affects colloidal form.
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(of animals and plants) to occupy or inhabit; live in or on.
Lions affect Africa. Moss affects the northern slopes.
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Archaic.
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to have affection for; fancy.
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to aim at; aspire to.
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verb (used without object)
verb
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to put on an appearance or show of; make a pretence of
to affect ignorance
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to imitate or assume, esp pretentiously
to affect an accent
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to have or use by preference
she always affects funereal clothing
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to adopt the character, manner, etc, of
he was always affecting the politician
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(of plants or animals) to live or grow in
penguins affect an arctic climate
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to incline naturally or habitually towards
falling drops of liquid affect roundness
verb
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to act upon or influence, esp in an adverse way
damp affected the sparking plugs
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to move or disturb emotionally or mentally
her death affected him greatly
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(of pain, disease, etc) to attack
noun
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.
Synonym Usage
See pretend.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
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.
Vocabulary lists containing affect
The Vocabulary.com Top 1000
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PARCC: Language of the Test (Grade7)
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Jim Burke's Academic Vocabulary List
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
He says there's growing evidence which shows industrial processing does affect our health and that businesses control the food market in a way that is "very harmful".
From BBC ● Sep. 26, 2026
The senior FAA official said the outcome of the agency’s probe could affect the plane’s certification if regulators determine the glitch amounts to an unsafe condition that needs to be addressed.
From The Wall Street Journal ● Sep. 26, 2026
Field conditions in Rio de Janeiro could affect the strategies, especially with lots of players dealing with lower-body injuries.
From Los Angeles Times ● Sep. 24, 2026
The researchers also discovered an intriguing connection between NUDT5 and another protein called NUDT15, which is already known to affect how patients respond to thiopurine drugs.
From Science Daily ● Sep. 24, 2026
To find out more about harmonics and how they affect a musical sound, see Harmonic Series.
From "Understanding Basic Music Theory" by Catherine Schmidt-Jones and Russel Jones
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The outage affects an estimated 1.8 Bcf/d of natural gas from Appalachia.
From The Wall Street Journal ● Sep. 25, 2026
"All this affects people's ability to stay connected, study, work," he said.
From BBC ● Sep. 25, 2026
Osteoarthritis affects millions of people each year and can develop in many joints throughout the body.
From Science Daily ● Sep. 22, 2026
ALS is often diagnosed between the ages of 40 and 70 and affects both the forebrain and the hindbrain.
From Science Daily ● Sep. 21, 2026
Many educators have studied the role of gender and how it affects teachers and teaching.
From "Music and the Child" by Natalie Sarrazin
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.