| featherbrained(adjective, ability, careless, silly, foolish) |
| gaga(adjective, ability, informal, careless, foolish) |
| idiotic(adjective, weak, simple, knowledge, ability) |
| inane(adjective, careless, silly, foolish, stupid) |
| madcap(noun, adjective, careless, wild, silly) |
| reckless(adjective, careless, wild, silly, foolish) |
| thoughtless(careless, wild, crazy, vague, impulsive) |
| tomfool(adjective, knowledge, ability, foolish) |
| wild(adjective, careless, foolish, fantastic, thoughtless) |
| witless(adjective, weak, simple, silly, foolish) |
| adventurous(adjective, careless, wild, bold, thoughtless) |
| cockeyed(adjective, knowledge, ability, informal, extraordinary) |
| crackpot(impractical, half-baked, doomed) |
| featherheaded |
| half-baked(adjective, weak, simple, foolish, stupid) |
| heedless(adjective, careless, wild, silly, stupid) |
| nutty(adjective, weak, simple, wild, silly) |
| rattlebrained |
| ridiculous(adjective, weak, simple, wild, strange) |
| sappy(adjective, knowledge, slang, ability) |