Synonyms for Nonsensical:

adj.

absurd (adjective)
outlandish, inane, silly, incongruous, invalid, paradoxical, preposterous, implausible, goofy, senseless, idiotic, illogical, impossible, ludicrous, contradictory, irrational, absurd, eccentric, inconsistent, farcical, foolish, ridiculous, anachronistic, fallacious, loony, crazy, meaningless, bizarre, self-contradictory.
extreme (adjective)
extreme.
foolish (adjective)
lame-brained, moronic, imbecilic, cretinous, crackpot, blockheaded, foolish, nitwit, chuckle-headed, dim-witted, brainless, dumb, goofy, inane, doltish, knuckle-headed, half-witted, loony, crazy, meat-headed, idiotic, absurd, dippy, ignorant, loopy, asinine, dotty, tomfool, dopey, blithering, bone-headed.
meaningless (adjective)
blathering, noisy, gobbledygook, cryptic, jabbering, double talk, absurd, unmeaning, meaningless, Driveling, senseless, hogwash.
ridiculous (adjective)
curious, crazy, bizarre, grotesque, silly, comical, foolish, incredible, preposterous, laughable, poppycock, eccentric, ludicrous, outlandish, farcical, ridiculous, dubious, outrageous, absurd, oddball, weird.
softheaded (adjective)
softheaded.

n.

perverse, hysterical, childish, extreme, irresponsible, wrong. unearthly, loopy, mad, insane, harebrained, lunatic, knowledge, balmy, tomfool, sappy, ability, zany, softheaded, wacky, dippy, jerky. nonsensical (noun)
nonsense, foolish, preposterous, derisory, ridiculous, ludicrous, laughable, meaningless, absurd.

Other synonyms:

wacky, softheaded, jerky, dippy, loopy. extreme, harebrained. zany, lunatic, sappy. insane, unearthly. mad. Other relevant words:
tomfool, irresponsible, childish, extreme, absurd, insane, derisory, balmy, harebrained, wacky, mad, softheaded, zany, nonsense, dippy, loopy, lunatic, sappy, jerky, unearthly.

Usage examples for nonsensical

  1. " David is telling us one of his nonsensical stories, sir," said she to Mr. Fountain, " and it is so interesting; go on, David." – Love Me Little, Love Me Long by Charles Reade Edition: 10 Language: English
  2. There are teachers and preachers who hold the interest of those taught by tickling their ears with material, either funny or nonsensical – Principles of Teaching by Adam S. Bennion