| cuckoo(adjective, slang, silly, foolish, stupid) |
| potty(adjective, wild, silly, foolish, crazy) |
| wacky(adjective, slang, unusual, wild, strange) |
| barmy(adjective, silly, foolish, crazy) |
| daffy(adjective, simple, informal, silly, foolish) |
| fruity(adjective, slang, informal, silly, foolish) |
| out to lunch(expression, adjective, idiom, silly) |
| irrational(adjective, wrong, unusual, wild, strange) |
| maniacal(adjective, silly, foolish, stupid, crazy) |
| buggy(adjective, slang, silly, foolish, crazy) |
| dippy(adjective, silly, foolish, insane) |
| kooky(adjective, unusual, wild, strange, silly) |
| psycho(silly, foolish, crazy, insane) |
| bats in the belfry(expression, idiom, silly, foolish) |
| berserk(adjective, silly, foolish, crazy) |
| delirious(adjective, silly, foolish, crazy) |
| flipped out(expression, silly, foolish, crazy) |
| freaked out(expression, silly, foolish, insane) |
| mad as a March hare(expression, idiom, silly, foolish) |
| mad as a hatter(expression, adjective, idiom, silly, foolish) |