Synonyms and related words :
balmy, bananas, barmy, bats, batty, beany, bonkers, buggy, bughouse, bugs, crackers, cuckoo, daffy, dippy, dotty, flaky, freaked-out, fruitcakey, fruity, gaga, goofy, haywire, just plain nuts, kooky, loony, loopy, nuts, nutty, off the hinges, off the track, off the wall, potty, round the bend, screwball, screwballs, screwy, slaphappy, wacky