FALLACIOUS Synonyms: 187 Similar and Opposite Words

fallacious

adjective

fə-ˈlā-shəs

Definition of fallacious

as in unreasonable

not using or following good reasoning it's fallacious to say that something must exist because science hasn't proven its nonexistence

Synonyms & Similar Words

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Antonyms & Near Antonyms

as in misleading

tending or having power to deceive consumers who harbor the fallacious belief that credit-card spending will never catch up with them

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Antonyms & Near Antonyms

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of fallacious There is a widespread but fallacious perception that India's tariffs are inordinately high. — Mohan Kumar, MSNBC Newsweek, 31 Aug. 2025 The same economists who believe in the same fallacious economic notions? — John Tamny, Forbes.com, 6 July 2025 That will in turn spread on social media, which often plays a disproportional role in boosting these disinformation efforts by providing nearly unlimited platforms for unfiltered content and fallacious and deceptive claims. — Peter Suciu, Forbes, 23 Dec. 2024 There might be a bigger market for these products, and more consumers might be immune to the fallacious argument that they’re overly processed, if more people were persuaded of the ills of factory farming. — Kenny Torrella, Vox, 7 Dec. 2018 See All Example Sentences for fallacious

Recent Examples of Synonyms for fallacious

Adjective

Your expectations of your stepsons aren’t unreasonable at all.

— R. Eric Thomas, Mercury News, 27 Aug. 2026
If the prosecution’s version of the evidence is reasonable and the defense’s is unreasonable, then that is not reasonable doubt.

— Christine Pelisek, PEOPLE, 25 Aug. 2026

Definition of unreasonable

Adjective

Blanche is also confronting growing distrust of the Justice Department among judges, who in multiple cases have accused government lawyers of withholding information or misleading courts.

— Alanna Durkin Richer, Chicago Tribune, 28 Aug. 2026
Both made misleading statements when questioned by authorities, according to the lawsuit.

— Chase Jordan August 27, Charlotte Observer, 27 Aug. 2026

Definition of misleading

Adjective

But the question remained unsolved for polygons with irrational angles.

— Sam Macdonald, Scientific American, 14 Aug. 2026
As a result, the argument goes, today's spending is irrational because the hardware would need to be replaced too frequently to generate an attractive return on investment, known as ROI.

— , CNBC, 12 Aug. 2026

Definition of irrational

Adjective

The technology was also tested against deceptive behaviour, an in a different scenario, fishing boats appeared to retreat while vessels from another direction accelerated toward the coastguard ship.

— Bojan Stojkovski, Interesting Engineering, 30 Aug. 2026
The siblings are likely to dispute Jeanie’s characterization of their actions as deceptive and clandestine, perhaps by pointing to communications with their sister and her responses.

— Michael McCann, Sportico.com, 28 Aug. 2026

Definition of deceptive

Adjective

But in each event—in the living act, the undoubted deed—there, some unknown but still reasoning thing puts forth the mouldings of its features from behind the unreasoning mask.

— Literary Hub, Literary Hub, 6 July 2026
Roosevelt surely understood that nameless, unreasoning, unjustified fear cannot be eradicated.

— New York Times, New York Times, 9 June 2026

Definition of unreasoning

Adjective

The lawsuit filed by two former employees contains allegations that are false, misleading, and unsupported by credible evidence.

— Devon Henderson, New York Times, 2 Sep. 2026
Zucker provided false and misleading statements to investigators, according to a summary of findings released Wednesday.

— Dan Mangan, CNBC, 2 Sep. 2026

Definition of false

Adjective

The researchers suspect that others were created by AI that either hallucinated or, just like the AI agents browsing their file, couldn’t distinguish between legitimate and illegitimate instructions.

— Dan Goodin, ArsTechnica, 27 Aug. 2026
Internet discussions portrayed the SPLC as a politically motivated or illegitimate actor.

— Art Jipson, The Conversation, 20 Aug. 2026

Definition of illegitimate

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“Fallacious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/fallacious. Accessed 4 Sep. 2026.

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Synonyms of fallacious

adjective

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