affect
1 Americanverb (used with object)
noun
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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:
This change didn’t affect how the CDC detects and investigates outbreaks; for that it relies on a separate reporting system that collects case and genetic sequencing information from labs.
From The Wall Street Journal ● Jul. 22, 2026
Cuts in rates particularly affect those who rely on the interest from their savings to top up their income.
From BBC ● Jul. 22, 2026
The activist said he’s seen AI affect ride-hail drivers, therapists, architects, designers and other professions.
From Los Angeles Times ● Jul. 22, 2026
Beyond offering new insight into an elusive whale species, the findings raise broader questions about how bacterial infections may affect marine wildlife and ocean health.
From Science Daily ● Jul. 21, 2026
Whether a stem points up or down does not affect the note length at all.
From "Understanding Basic Music Theory" by Catherine Schmidt-Jones and Russel Jones
Scientists need a clearer understanding of why people respond differently and how each caffeine source affects cardiovascular health.
From Science Daily ● Jul. 22, 2026
Lawmakers agreed on the need for regulation, as warnings have multiplied over the harmful affects of social media on children.
From Barron's ● Jul. 21, 2026
How much the computing power behind it affects people’s lives and the environment will also contribute.
From The Wall Street Journal ● Jul. 21, 2026
As a health economist who studies how insurance coverage affects people’s health, I see the drop as more than a numbers story.
From Salon ● Jul. 19, 2026
“If it affects Darin,” I say, “I need to worry about it. Is it Mazen? Has he changed his mind?”
From "An Ember in the Ashes" by Sabaa Tahir
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.