irrational Definition

  • 1not logical or reasonable
  • 2not based on reason or clear thinking

Using irrational: Examples

Take a moment to familiarize yourself with how "irrational" can be used in various situations through the following examples!

  • Example

    It's irrational to be afraid of spiders.

  • Example

    Her decision was completely irrational.

  • Example

    His behavior was so irrational that we had to call the police.

  • Example

    The idea of spending all that money on a car seems irrational to me.

irrational Synonyms and Antonyms

Phrases with irrational

  • a real number that cannot be expressed as a ratio of two integers


    Pi is an irrational number.

  • an excessive or unreasonable fear of something


    His irrational fear of heights prevented him from going on the roller coaster.

  • behavior that is not based on reason or clear thinking


    Her irrational behavior caused her to lose her job.

Origins of irrational

from Latin 'irrationalis', from 'in-' (not) + 'rationalis' (reasonable)


Summary: irrational in Brief

The term 'irrational' [ɪˈræʃənl] refers to something that is not logical or reasonable, and is not based on reason or clear thinking. It can describe anything from a fear to a decision, as in 'Her decision was completely irrational.' 'Irrational' also has specific meanings in mathematics, such as 'irrational number,' which cannot be expressed as a ratio of two integers.

How do native speakers use this expression?