| crazy(adjective, strange, silly, foolish, insane) |
| nutty(noun, adjective, slang, silly, foolish) |
| bonkers(adjective, informal, silly, foolish, mad) |
| loony(adjective, informal, silly, foolish, insane) |
| wacky(adjective, slang, silly, foolish, mad) |
| balmy(adjective, silly, foolish, unwise) |
| nuts(adjective, slang, silly, foolish, mad) |
| barmy(adjective, silly, foolish, mad, insane) |
| batty(adjective, slang, silly, foolish, mad) |
| buggy(adjective, slang, insane, sane) |
| crackers(adjective, insane, sane) |
| kooky(adjective, silly, foolish, mad, insane) |
| loopy |
| bats |
| cuckoo(adjective, slang, silly, foolish, mad) |
| daft(adjective, silly, foolish, mad, insane) |
| dotty(adjective, insane, sane) |
| haywire |
| loco(adjective, slang, mad, insane, sane) |
| lunatic(adjective, silly, foolish, mad, insane) |