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

Loss aversion, sunk-cost fallacy and herd behavior — all of it kicks in during a drawdown.

From MarketWatch • May 12, 2026

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

From The Wall Street Journal • Nov. 13, 2025

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

From Salon • Aug. 28, 2025

It’s a common fallacy to envision these species as arranged in a straight line of descent, with Ergaster begetting Erectus, Erectus begetting the Neanderthals, and the Neanderthals evolving into us.

From "Sapiens: A Brief History of Humankind" by Yuval Noah Harari

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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