Synonyms and Antonyms of crackbrained
- had the crackbrained idea that he was receiving radio signals from outer space
balmy, barmy [chiefly British], bats, batty, bedlam, bonkers, brainsick, bughouse [slang], certifiable, cracked, crackers, crackpot, cranky [dialect], crazed, crazy, cuckoo, daffy, daft, demented, deranged, fruity [slang], gaga, haywire, insane, kooky (also kookie), loco [slang], loony (also looney), loony tunes (or looney tunes), lunatic, mad, maniacal (also maniac), mental, meshuga (or meshugge), moonstruck, non compos mentis, nuts, nutty, psycho, psychotic, scatty [chiefly British], screwy, unbalanced, unhinged, unsound, wacko (also whacko), wacky (also whacky), wud [chiefly Scottish]
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