Meaning of irrational

ir•ra•tion•al

Pronunciation: (i-rash'u-nl), [key]
— adj.
  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.
    1. (of a number) not capable of being expressed exactly as a ratio of two integers.
    2. (of a function) not capable of being expressed exactly as a ratio of two polynomials.
  5. (of an equation) having an unknown under a radical sign or, alternately, with a fractional exponent.
    1. of or pertaining to a substitution in the normal metrical pattern, esp. a long syllable for a short one.
    2. noting a foot or meter containing such a substitution.
—n.
  1. See
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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