IRRATIONAL Synonyms: 89 Similar and Opposite Words

irrational

adjective

i-ˈra-sh(ə-)nəl

Definition of irrational

as in unreasonable

not using or following good reasoning it's irrational to think that you can continue to consume an excess of calories and not gain weight

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Example Sentences

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Recent Examples of irrational Retailers’ reputations as poor environments for technology innovation is not unjustified, but their behavior is not completely irrational either. — Richard Kestenbaum, Forbes.com, 23 July 2026 In both cases, cheap credit fueled the irrational exuberance. — Annie Lowrey, The Atlantic, 21 July 2026 An irrational holding on to the possibility of a comeback, if that was the word if no one noticed you’d retired in the first place. — Literary Hub, 17 July 2026 Their ideas about it were often steeped in stereotypes suggesting that Buddhists were irrational and childish in their thinking. — Livia Gershon, JSTOR Daily, 7 July 2026 See All Example Sentences for irrational

Recent Examples of Synonyms for irrational

Adjective

The parties have blamed each other for trying to make unreasonable last-minute changes to their agreement.

— Kevin Breuninger,Michael Wayland, CNBC, 24 Aug. 2026
The investigation found Brazilian policies unreasonable or discriminatory toward US commerce.

— Joshua Hong, Fortune, 21 Aug. 2026

Definition of unreasonable

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 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