| kook(noun, slang, mad, sick, wise) |
| mental(noun, adjective, slang, silly, mad) |
| mentally ill(expression, adjective, idiom, sane, unwell) |
| silly(adjective, foolish, stupid, crazy, mad) |
| zany(noun, silly, foolish, unwise, comical) |
| crank(noun, informal, mad, wise, schizophrenic) |
| crow(noun, verb, bird, ululation, ululate) |
| jackass |
| kooky(adjective, silly, foolish, crazy, mad) |
| loon(noun, slang, informal, mad, sick) |
| non compos mentis(adjective, law, sane) |
| not all there(noun, expression, adjective, idiom, slang) |
| of unsound mind(expression, adjective, idiom, silly, mad) |
| preposterous(adjective, silly, foolish, stupid, unwise) |
| stupid(adjective, silly, foolish, unwise) |
| trill(noun, verb, ululation, ululate) |
| warble(noun, verb, ululation, ululate) |
| ape(silly, foolish, crazy, mad, insane) |
| bats |
| bozo |