Also found in: Thesaurus, Medical, Legal, Encyclopedia.
a. Not endowed with reason.
b. Affected by loss of usual or normal mental clarity; incoherent, as from shock.
c. Marked by a lack of accord with reason or sound judgment: an irrational dislike.
a. Being a syllable in Greek and Latin prosody whose length does not fit the metric pattern.
b. Being a metric foot containing such a syllable.
3. Mathematics Of or relating to an irrational number.
An irrational number.