| insane(noun, adjective, impractical, eccentric, half-baked) |
| crazy(noun, adjective, person, foolish, mad) |
| lunatic(noun, adjective, person, crazy, mad) |
| loony(noun, adjective, person, informal, foolish) |
| maniac(noun, person, crazy, mad, eccentric) |
| screwball(noun, adjective, person, character, slang) |
| kook(noun, person, character, slang, crazy) |
| madman(noun, adjective, person, crazy, mad) |
| nut(noun, character, slang, crazy, mad) |
| psychotic(noun, adjective, person, mad, madness) |
| crank(noun, informal, crazy, mad, original) |
| bedlamite(noun, person, character, crazy, nut) |
| mad(adjective, crazy, odd, insane, lunatic) |
| wild(adjective, crazy, mad, odd, insane) |
| freak(noun, person, crazy, nut, fanatic) |
| nutcase(noun, character, nut, fanatic, freak) |
| psycho(noun, person, mad, nut, fanatic) |
| psychopath(noun, person, crazy, mad, nut) |
| absurd(adjective, foolish, crazy, mad, odd) |
| oddball(noun, adjective, character, crazy, eccentric) |