| empty(adjective, characteristic, slight, detail, small) |
| juvenile(adjective, characteristic, stupidity, foolishness) |
| loony(adjective, light, weak, simple, wrong) |
| sappy(adjective, soft, knowledge, slang, ability) |
| wild(adjective, wrong, strange, foolish, stupid) |
| imbecile(noun, adjective, dull, simple, fool) |
| thoughtless(adjective, feature, state, wrong, condition) |
| dumb(adjective, foolish, stupid, crazy, vague) |
| zany(adjective, weak, simple, knowledge, ability) |
| fulmar(noun, person, foolishness, idiocy) |
| goof(noun, person, foolishness, idiocy) |
| gosling(noun, person, foolishness, idiocy) |
| hare-brained(adjective, foolish, crazy, zany) |
| mutt(noun, person, foolishness, idiocy) |
| noddy(noun, person, foolishness, idiocy) |
| scatterbrained(adjective, ability) |
| batty(adjective, light, wild, foolish, stupid) |
| shallow(adjective, slight, detail, small, foolish) |
| light-headed |
| nuts(adjective, wild, foolish, stupid, crazy) |