| mentally strange(expression, silly, foolish, insane) |
| nutty as fruitcake(expression, idiom, silly, foolish) |
| round the bend(expression, idiom, silly, foolish) |
| screw loose(expression, silly, foolish, insane) |
| absurd(adjective, simple, wild, silly, foolish) |
| ape(silly, foolish, crazy, insane) |
| bedlamite(adjective, simple, silly, foolish, crazy) |
| dingy(silly, foolish, insane, unwise) |
| erratic(unusual, strange, silly, foolish) |
| flaky(adjective, simple, silly, foolish) |
| flipped(silly, foolish, insane, unwise) |
| foolish(adjective, simple, wild, silly, stupid) |
| harebrained(adjective, wild, silly, foolish, stupid) |
| idiotic(simple, silly, foolish, stupid) |
| keen(adjective, sympathetic, excited, silly, foolish) |
| ridiculous(adjective, simple, wild, silly, foolish) |
| schizo(silly, foolish, insane, unwise) |
| screwball(adjective, silly, foolish, crazy) |
| silly(simple, foolish, stupid, insane) |
| unglued(silly, foolish, unstable, insane) |