Definitions

fallacy

[fal-uh-see] / ˈfæl ə si /

NOUN

illusion, misconception

Synonyms

STRONGEST

deception falsehood heresy inconsistency misinterpretation paradox untruth

STRONG

aberration ambiguity artifice bias casuistry cavil deceit deceptiveness delusion deviation elusion equivocation erratum erroneousness error evasion faultiness flaw illogicality inexactness invalidity misapprehension miscalculation misconstrual mistake notion perversion preconception prejudice quirk solecism sophism sophistry speciousness subterfuge

WEAK

non sequitur quibbling

Antonyms

STRONGEST

truth

STRONG

accuracy certainty conformity correction directness facing fairness frankness honesty meeting openness reality sameness truthfulness

WEAK

evidence fact right surety

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.

"This is the sunk cost fallacy," he said, adding that "it keeps the addictive behaviour loop".

From Barron's • May 31, 2026

If you’re thinking, “I won’t be able to get the money for my great business idea,” that is a psychological fallacy.

From MarketWatch • May 6, 2026

“This crisis is not a fallacy nor a thinly veiled threat.”

From The Wall Street Journal • Mar. 15, 2026

The promise is that we can shape behavior; the fallacy is that the power rarely reaches beyond cosmetic concessions.

From Salon • Aug. 28, 2025

Doing so is sometimes termed the “broad base” fallacy, and we’ve already cited a couple of instances of it.

From "Innumeracy: Mathematical Illiteracy and Its Consequences" by John Allen Paulos

Vocabulary lists containing fallacy

Argumentative Writing

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TEKS ELAR Academic Vocabulary List (5th-7th grades)

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Power Suffix: -acy

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