irrational

[ih-rash-uh-nl, -rash-nl] / ɪˈræʃ ə nl, -ˈræʃ nl /

ADJECTIVE

illogical, senseless

Synonyms

STRONGEST

aberrant absurd crazy foolish incoherent insane preposterous ridiculous stupid unreasonable unsound unwise wrong

STRONG

invalid loony raving silly wild

WEAK

brainless cockamamie delirious demented disconnected disjointed distraught fallacious flaky freaky injudicious kooky mad mindless nonsensical nutty off-the-wall reasonless sophistic specious unreasoning unstable unthinking wacky

Antonyms

STRONGEST

balanced logical rational realistic reasonable responsible sane sensible serious smart sound thoughtful well wise

WEAK

reflective stable

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.

"The railway is part of the rationalisation of our transport system, especially on the Uganda side, which is irrational and wasteful," the veteran leader told the ceremony.

From Barron's • Mar. 21, 2026

While the motives that drive a knight are often human, political, or both, the logic is as miraculous and irrational as a muddy hedge knight crawling out from under a fallen dragon.

From Salon • Feb. 25, 2026

Freight was another sector that some analysts said was subjected to irrational AI fears last week.

From MarketWatch • Feb. 17, 2026

Knowing they’ve lost the chance at a fortune, people will sometimes take irrational risks to make it back.

From The Wall Street Journal • Feb. 9, 2026

I decided that my wild and irrational desire was merely a vagrant impulse, and that it would not occur again.

From "Newjack: Guarding Sing Sing" by Ted Conover

Vocabulary lists containing irrational

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