Adjective "irrational" definition and examples



Definitions and examples


Not logical or reasonable.
  1. 'By absurd, I do not mean silly, but absurd as is in the illogical or irrational.'
  2. 'Booze and cocaine corroded his sanity and left him with a legacy of irrational behaviour.'
  3. 'Solutions that would seem logical to us would seem totally irrational to them.'
  4. 'She had never known for her daughter to be so irrational, so crazy.'
  5. 'Without that insight, a supplier can encounter fewer surprises by evaluating even seemingly irrational scenarios.'
  6. 'Australians aren't at all used to visceral and irrational hatred directed at them.'
  7. 'The more irrational and illogical someone becomes, the more logical and incisive I become.'
  8. 'Crowds and mobs are not completely irrational, but they have their own logic.'
  9. 'Home values have soared to high levels in many countries as irrational exuberance grips the markets.'
  10. 'The author of the piece argues that our attitude towards it is mostly irrational prejudice.'
  11. 'Man is an irrational being, morals are irrational, and have no metaphysical foundation which make them "real" or worth paying any attention to.'
(of a number, quantity, or expression) not expressible as a ratio of two integers, and having an infinite and non-recurring expansion when expressed as a decimal. Examples of irrational numbers are the number π and the square root of 2.
  1. 'A transcendental number is an irrational number that is not a root of any polynomial equation with integer coefficients.'
  2. 'What about a seed angle derived from the golden ratio, an irrational number?'


An irrational number or quantity; a surd.
  1. 'His commentary to Euclid is of interest because of its discussion of unordered irrationals.'
  2. 'Eudoxus's definition of equal ratios corresponds exactly to the modern theory of irrationals.'


1. without the faculty of reason; deprived of reason.

2. without or deprived of normal mental clarity or sound judgment.

3. not in accordance with reason; utterly illogical: irrational arguments.

4. not endowed with the faculty of reason: irrational animals.

5. Mathematics. (of a number) not capable of being expressed exactly as a ratio of two integers. (of a function) not capable of being expressed exactly as a ratio of two polynomials.

6. Algebra. (of an equation) having

More examples(as adjective)

"situations can be irrational to people."

"governments can be irrational of lives."

"dates can be irrational of classes."

"exuberances can be irrational."

"behaviours can be irrational."

More examples++


Late Middle English: from Latin irrationalis, from in- ‘not’ + rationalis (see rational).