irrational

ir-ra-tion-al · adjective

imported

Definitions

adjective

  1. 1.

    Not based on reason or clear thinking; not logical.

  2. 2.

    (Mathematics) Of a number that cannot be expressed as a simple fraction; having an infinite, non-repeating decimal expansion.

Phrases & expressions

  • •
    irrational fear — a fear not based on realistic danger
  • •
    irrational behavior — actions that defy logical explanation
  • •
    irrational number — a number that cannot be expressed as a fraction

Related words

Antonyms: logical, rational, reasonable
See also: illogical, rational, unreasonable
Synonyms: absurd, illogical, unreasonable

Etymology

From Latin irrationalis, from in- ("not") + rationalis ("rational"), from ratio ("reason, calculation").