Synonyms for Irrational:
implausible, crazy, ludicrous, ridiculous, foolish, outlandish, preposterous, illogical, farcical, impossible, idiotic, bizarre, invalid, anachronistic, paradoxical, senseless, nonsensical, silly, inane, incongruous, contradictory, fallacious, inconsistent, absurd, self-contradictory, meaningless, eccentric.
•illogical, senseless (adjective)
foolish, reasonless, kooky, ridiculous, demented, fallacious, delirious, nutty, silly, absurd, crazy, nonsensical, incoherent, preposterous, insane, mad, invalid, specious, wrong, unreasoning.
crazy, lunatic, deranged, hysterical, delirious, schizoid, blithering, nutty, frenzied, babbling, insane, batty, kooky, psycho, Crack-brained, berserk, psychotic, mad, brain-sick, unbalanced, maniacal, neurotic, feverish, demented.
n.extreme, childish, perverse, irresponsible. Unreasoned, out of bounds, reason. •illogical (noun)
untenable, wrong, specious.
jaundiced, unreasoning, blind, nonrational, superstitious, yellow, reasonless, incoherent.
Usage examples for irrational
By commending irrational retrogression from active use of the understanding back to dreamy contemplation? – Rousseau Volumes I. and II. by John Morley
2. Scientifically: Cleanliness, as practised, is conventional and irrational – A Poor Man's House by Stephen Sydney Reynolds