Definitions

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.

There are many places to point fingers when reckoning with our new, irrational state of affairs.

From Slate • Apr. 26, 2026

However, she said she had experienced fear and irrational guilt after Eliza's diagnosis.

From BBC • Mar. 22, 2026

"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

“Targeting Gulf states is completely irrational, and very shortsighted.”

From The Wall Street Journal • Mar. 1, 2026

Even healthy people cried and said irrational things when their parents died.

From "Kindred" by Octavia Butler

Vocabulary lists containing irrational

Pi Day Vocabulary

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The Number System

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Divergent

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