Synonyms of hare-brained

1 Syllable
wild, daft, odd, mad, nuts
2 Syllables
wacky, crazed, silly, zanier, screwy, zaniest, foolish, zany, loony, balmy, nutty, wackier, absurd, wackiest, fooler, crazy
3 Syllables
erratic, insane, lunatic, demented, eccentric, deranged
4 Syllables
irrational, preposterous
5 Syllables
unpredictable