| empty-headed(silly, foolish, stupid) |
| go for broke |
| hare-brained(adjective, silly, foolish, crazy, zany) |
| harebrained(adjective, weak, simple, wild, silly) |
| inept |
| maddened(adjective, insanity) |
| not right(expression, idiom, crazy, insanity, cuckoo) |
| outlandish(adjective, silly, foolish, ridiculous, absurd) |
| scatterbrained(adjective, simple, slow, foolish, stupid) |
| screwball(adjective, silly, foolish, crazy, mad) |
| simpleminded(silly, foolish, stupid) |
| slow-witted |
| twisted(adjective, crazy, mad, odd, insane) |
| unintelligent(adjective, weak, simple, slow, silly) |
| unsane(adjective, crazy, mad, odd, insane) |
| unwise(adjective, weak, simple, wild, silly) |
| weak-minded |
| weird(strange, silly, foolish, odd, unwise) |
| avid(feature, character, behavior) |
| bats in the belfry(expression, idiom, silly, foolish, mad) |