"loony" in the noun sense
1. crazy, loony, looney, nutcase, weirdo
someone deranged and possibly dangerous
"loony" in the adjective sense
1. balmy, barmy, bats, batty, bonkers, buggy, cracked, crackers, daft, dotty, fruity, haywire, kooky, kookie, loco, loony, loopy, nuts, nutty, round the bend, around the bend, wacky, whacky
informal or slang terms for mentally irregular
"it used to drive my husband balmy"
Source: WordNet® (An amazing lexical database of English)
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