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

"I think the thing young founders get wrong is they view hours worked in and of itself as necessary and sufficient to think of themselves as productive. And that's where the fallacy lies", he explains.

From BBC • Feb. 8, 2026

The sunk-cost fallacy tempts people to pay escalating premiums because they’ve paid for so long.

From MarketWatch • Nov. 15, 2025

That would be a fallacy, but Mr. Bottum didn’t commit it.

From The Wall Street Journal • Nov. 13, 2025

Naturally, I don’t subscribe to the obvious fallacy that every society promptly adopts every innovation that would be useful for it.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond

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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