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

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

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.

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

Irrationality is cognition, thinking, talking, or acting without rationality. Irrationality often has a negative connotation, as thinking and actions that are less useful or more illogical than other …

Dec 20, 2025 · Adjective [edit] irrational (comparative more irrational, superlative most irrational) Not rational; unfounded, nonsensical or wrong-headed. quotations an irrational decision

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

irrational, adj. & n. meanings, etymology, pronunciation and more in the Oxford English Dictionary