ridiculous, silly, nonsensical, senseless, outlandish,
preposterous, farcical, mad, stupid, foolish, idiotic, imbecilic
or imbecile, moronic, childish
laughable, ludicrous, risible, inane, Colloq crazy, nutty, nuts , Chiefly Brit daft
asinine, senseless, illogical, irrational, unreasoned,
unreasonable, incongruous, paradoxical, unsound, meaningless