Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “irrational”

See all translations

irrational

adjective uk   /ɪˈræʃ.ən.əl/ us  
C2 not using reason or clear thinking: It's totally irrational, but I'm frightened of mice. His parents were worried by his increasingly irrational behaviour.
irrationally
adverb uk   /-i/ us  
People often behave irrationally when they are under stress.
irrationality
noun [U] uk   /ɪˌræʃ.ənˈæl.ə.ti/ us    /-t̬i/
Translations of “irrational”
in Spanish irracional, absurd…
in Chinese (Traditional) 不理智的,沒有理性的…
in Russian нерациональный…
in Turkish mantıksız, saçma, akla dayanmayan…
in Chinese (Simplified) 不理智的,没有理性的…
in Polish irracjonalny…
(Definition of irrational from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
What is the pronunciation of irrational?
Add Cambridge dictionaries to your browser to your website

More meanings of “irrational”

Definitions of “irrational” in other dictionaries

Word of the Day

pot luck

anything that is available or is found by chance, rather than something chosen, planned, or prepared

Word of the Day

Think long and hard; the language of decisions

by Liz Walter,
January 28, 2015
One of the best ways (perhaps the best way) to improve your English is to learn how words go together in phrases, idioms, or other patterns such as verb/noun or adjective/noun pairs (often called ‘collocations’). This blog looks at some useful phrases and collocations connected with the subject of decisions, something we

Read More 

micro pig noun

January 26, 2015
an extremely small pig, bred to be a pet Micro pigs have become popular pets recently, with famous owners including Victoria Beckham, Paris Hilton and Olympic diver, Tom Daley.

Read More