Englishabsurd
adjective
what an absurd idea!:
preposterous, ridiculous, ludicrous, farcical, laughable, risible;
idiotic, stupid, foolish, silly, inane, imbecilic, insane, harebrained;
unreasonable, irrational, illogical, nonsensical, pointless, senseless;
outrageous, shocking, astonishing, monstrous, fantastic, incongruous, grotesque;
unbelievable, incredible, unthinkable, implausible;
informal crazy;
British, informal barmy, daft.
▷antonyms reasonable, sensible.