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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Recent Examples of irrational Thanks to this fit of irrational exuberance, the NBA realized the benefits of cap smoothing and more-friendly contract-extension language in the collective bargaining agreement. — John Hollinger, New York Times, 1 July 2026 The reflex, from a distance, is to call this irrational. — Tyler Evans, Sun Sentinel, 28 June 2026 If people believe regulatory caution invalidates every legal claim, courts may look irrational. — Alex Smolak, STAT, 27 June 2026 Does pot make users irrational? — Morgan Marietta, The Conversation, 26 June 2026 See All Example Sentences for irrational

Recent Examples of Synonyms for irrational

Adjective

From the second Eldridge was drafted, a little devil appeared on your shoulder and whispered unreasonable expectations into your ear.

— Grant Brisbee, New York Times, 13 July 2026
In a poll on the post, 95% voted that this parent is NOT being unreasonable.

— Melissa Willets, Parents, 12 July 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

But that’s forcing them to wrestle with the idea that any action taken by a party is illegitimate, anti-democratic rigging — something the other team can use to depress the base.

— David Weigel, semafor.com, 22 July 2026
Signature-matching efforts sometimes disqualify more legitimate than illegitimate ballots.

— Jeremy Kohler, ProPublica, 15 July 2026