Synonyms for

Irrational

Verb / ˌɪˈræʃʌnʌl / Another word for irrational — explore alternatives below. For syllable breakdowns and pronunciation, see this word on Syllablesworld.

Definition

not logical or reasonable

Synonyms & similar words

rational irrationalnumber illogical unreasonable absurd crazy foolish senseless unfounded unjustifiable unjustified unreasonable unsound illogical preposterous ridiculous unrealistic baseless groundless invalid nonsensical unsupported

Synonyms by register

Formal

unreasonable illogical incoherent unjustified

Informal

crazy nuts bonkers out of line

Literary

unhinged beserk frenzied

Antonyms

rational logical reasonable sensible sound coherent justifiable

Common collocations

  • irrational behavior
  • irrational fear
  • irrational exuberance
  • irrational numbers
  • irrational decision
  • irrational thoughts
  • irrational anger

Word family

noun irrationality
adjective irrational
adverb irrationally

Usage note

Often used to describe behavior or emotions that lack logic or reason. Can also refer to mathematical numbers that cannot be expressed as a simple fraction.

Example sentences

  1. It's irrational to think that ice cream is healthy for breakfast.
  2. She had an irrational fear of spiders.
  3. It's irrational to spend all your money on toys.
  4. His decision was irrational and caused a lot of problems.
  5. It's irrational to believe that the earth is flat.

Quotes

  • The irrationality of a thing is not an argument against its existence, rather, a condition of it.
  • Irrationality is the square root of all evil.
  • Irrationality is the enemy of art, pure and simple.

Try these popular words

the and that for you with was this are have not from

Practice

Play the Word Synonyms game · Choose level (start near 1)

Worksheets

Grade 4 · Grade 5 · Grade 6

Topics

Guides

Explore more words