1. irrational That is absurd which is contrary to the first principles of reasoning; as, that a part should be greater than the whole is absurd. A paradoxical statement appears at first thought contradictory Synonyms: absurd, anomalous, ill-considered, ludicrous, ridiculous, chimerical, ill-judged, mistaken, senseless, erroneous, inconclusive, monstrous, stupid, false, incorrect, nonsensical, unreasonable, foolish, infatuated, paradoxical, wild, ill-advised, irrational, preposterous Antonyms: certain, incontrovertible, rational, substantial, consistent, indisputable, reasonable, true, demonstrable, indubitable, sagacious, undeniable, demonstrated, infallible, sensible, unquestionable, established, logical, sound, wise, incontestable
Synonyms for irrational 
