Synonyms of irrational

1 Syllable

mad, wrong, rash, queer, maer, wild

2 Syllables

wacky, kooky, queerer, schizoid, queerest, madder, stupid, loony, moonstruck, freaky, loopy, furious, mad-dog, ultraist, tomfool, wiggly, sillier, witless, distraught, nutty, maddest, specious, crazy, silly, nuttiest, loco, schizzo, whacko, absurd, wackiest, flaky, rabid, dippy, phobic, unsound, silliest, nuttier, smoking, raving, foolish, wackier, brainless, mindless, beastly

3 Syllables

off-the-wall, sophistic, fallacious, tottery, invalid, tottering, ireful, lunatic, senseless, phrenetic, unwise, unthinking, disjointed, ill-founded, overboard, demented, reasonless, unstable, insane, softheaded, fantastic, unscrewed, deranged, aberrant, uncurbed, birdbrained, judgmental, delirious, hare-brained

4 Syllables

unscientific, preposterous, injudicious, precipitant, corybantic, cockamamy, muddleheaded, unreasoning, cockamamie, disconnected, unreasoned, schizophrenic, nonsensical, arbitrary, illogical, lamebrained, imbecilic, ridiculous, emotional, bedlamite, incoherent, untempered, scatterbrained

5 Syllables

unreasonable, unmeasurable, ill-considered, inordinate, unconsidered, incohesive, overindulgent, unreflective