| silly(adjective, knowledge, ability, foolish, stupid) |
| nutty(adjective, slang, crazy) |
| insane(adjective, knowledge, ability, silly, foolish) |
| lunatic(adjective, knowledge, ability, silly, foolish) |
| wacky(adjective, knowledge, slang, ability, silly) |
| idiotic(adjective, simple, knowledge, ability, silly) |
| daffy(adjective, slang, crazy) |
| daft(adjective, weak, simple, silly, foolish) |
| balmy(adjective, knowledge, slang, ability, foolish) |
| batty(adjective, light, silly, stupid) |
| cuckoo(adjective, silly, foolish, insane) |
| nuts(adjective, slang, crazy) |
| screwy(adjective, light, silly, crazy) |
| bonkers(adjective, slang, crazy) |
| cockeyed(adjective, knowledge, slang, ability, informal) |
| kooky(adjective, weak, silly, foolish, crazy) |
| barmy(adjective, silly, foolish, insane) |
| potty(adjective, silly, foolish, insane) |
| bananas(adjective, slang, crazy) |
| deranged(adjective, silly, foolish, crazy) |