ridiculous

Synonyms absurd, cockamamy (or cockamamie), comical, derisive, derisory, farcical, laughable, ludicrous, pathetic, preposterous, risible, silly

Related Words asinine, brainless, dumb, fatuous, foolish, half-baked, half-witted, harebrained, idiotic (also idiotical), imbecile (or imbecilic), inane, jerky, moronic, nonsensical, simpleminded, stupid, unwise, weak-minded, witless; balmy, cockeyed, crazy, cuckoo, daffy, daft, dotty, insane, kooky (also kookie), loony (also looney), lunatic, mad, nutty, screwball, senseless, wacky (also whacky); fantastic (also fantastical), far-fetched, inconceivable, incredible, unbelievable, unreal, unrealistic, unreasonable; illogical, irrational

Phrases for the birds

Near Antonyms earnest, serious, solemn; believable, conceivable, credible, logical, rational, realistic, reasonable, sensible

Synonyms antic, chucklesome, comedic, comic, comical, droll, farcical, hilarious, humoristic, humorous, hysterical (also hysteric), killing, laughable, ludicrous, ridiculous, riotous, risible, screaming, sidesplitting, uproarious

Related Words amusing, diverting, entertaining; clownish, knockabout, slapstick, slapsticky, zany; facetious, flip, flippant, pert, smart, smart-aleck, smart-alecky, snickery; jocular, playful, waggish; campy, jokey (also joky); priceless, rich, whimsical, witty, wry; blithesome, gleeful, jocose, jocund, jolly, jovial, laughing, mad, merry, mirthful

Near Antonyms earnest, grave, no-nonsense, sedate, serious, severe, sober, sobersided, solemn, somber (or sombre), staid, unsmiling, weighty; affecting, moving, poignant, touching, tragic (also tragical); lachrymose, mournful, sad, sorrowful, tearful, woeful

Antonyms humorless, lame, unamusing, uncomic, unfunny, unhumorous, unhysterical