Synonyms for Moronic:

adj.

balmy (adjective)
loony.
dull (adjective)
unintellectual.
foolish (adjective)
nonsensical, crackpot, dumb, nitwit, asinine, absurd, dotty, blithering, foolish, cretinous, imbecilic, tomfool, ignorant, doltish, half-witted, bone-headed, dippy, crazy, goofy, brainless, dim-witted, meat-headed, lame-brained, dopey, zany, inane, blockheaded, loony, knuckle-headed, mentally retarded, loopy, chuckle-headed, idiotic.
insane (adjective)
balmy.
senseless (adjective)
asinine.
softheaded (adjective)
softheaded.
stupid (adjective)
brainless, imbecilic, dopey, inane, unintelligent, dumb, doltish, foolish, nonsensical, asinine, idiotic.
unintellectual (adjective)
unintelligent, half-wit, foolish, cretinous, unintellectual, idiotic, defective, imbecilic.

n.

silly, dippy, loopy, zany, harebrained, tomfool, wacky, softheaded, unearthly, insane, ability, jerky, sappy, knowledge, cockeyed, preposterous, balmy, lunatic, mad. moronic (noun)
unintelligent.

Other synonyms:

wacky, dippy, softheaded, jerky, loopy. harebrained, preposterous, cockeyed. silly, zany, sappy, lunatic. unearthly, insane. mad. Other relevant words:
balmy, loopy, tomfool, preposterous, unearthly, insane, cockeyed, silly, lunatic, mad, zany, dippy, sappy, harebrained, jerky, wacky, softheaded.