| besotted(adjective, simple, slow, stupid, boring) |
| bird-brained |
| birdbrained(adjective, dull, simple, slow, silly) |
| cracked(adjective, stupid, crazy, insane) |
| credulous(adjective, silly, stupid, green, fat) |
| dazed(dull, unintelligent, witless) |
| farcical |
| feather-brained |
| feeble(adjective, silly, stupid, green, fat) |
| flaky(adjective, silly, stupid, insignificant, unreasonable) |
| futile(adjective, dull, simple, slow, foolish) |
| harebrained(adjective, weak, simple, knowledge, ability) |
| injudicious(adjective, weak, simple, mind, think) |
| insensitive(slow, stupid) |
| kooky(weak, simple, silly, foolish, thoughtless) |
| loopy(adjective, knowledge, ability, informal, foolish) |
| meaningless(adjective, dull, simple, slow, silly) |
| mentally defective |
| mentally deficient(expression, silly, foolish, stupid) |
| mentally handicapped(expression, silly, foolish, stupid) |