The meaning of IRRATIONAL is not rational. How to use irrational in a sentence.

IRRATIONAL definition: without the faculty of reason; deprived of reason. See examples of irrational used in a sentence.

If you describe someone's feelings and behaviour as irrational, you mean they are not based on logical reasons or clear thinking. ...an irrational fear of science.

IRRATIONAL definition: 1. not using reason or clear thinking: 2. (of a number) that cannot be expressed as the ratio of…. Learn more.

Definition of irrational adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

irrational (ɪˈræʃənəl) adj 1. inconsistent with reason or logic; illogical; absurd 2. incapable of reasoning

irrational meaning, definition, what is irrational: not based on clear thought or reason: Learn more.

not having the power of reason: Brute animals are irrational beings. Mathematics (of a number) that cannot be expressed exactly as a ratio of two integers: The value of pi is an irrational …

Dec 20, 2025 · Noun irrational (plural irrationals) (mathematics) A real number that can not be expressed as the quotient of two integers, an irrational number.

IRRATIONAL meaning: 1 : not rational: such as; 2 : not thinking clearly not able to use reason or good judgment