| naive(adjective, simple, straightforward, innocent, green) |
| dim-witted(adjective, dull, simple, slow, foolish) |
| feeble-minded(adjective, dull, simple, ability, slow) |
| dull(adjective, simple, ability, slow, silly) |
| moronic(adjective, dull, simple, slow, silly) |
| simple(adjective, dull, ability, honest, slow) |
| half-witted(adjective, dull, simple, ability, slow) |
| jejune(simple, plain, fresh, innocent, sincere) |
| slow-witted(adjective, ability, backward) |
| stupid(adjective, dull, simple, slow, informal) |
| dumb(adjective, dull, simple, slow, silly) |
| imbecile(adjective, dull, simple, slow, silly) |
| imbecilic(adjective, simple, slow, silly, foolish) |
| dense(adjective, dull, simple, slow, silly) |
| empty-headed |
| foolish(adjective, silly, stupid, green, fat) |
| silly(adjective, foolish, stupid, green, fat) |
| slow(adjective, dull, simple, ability, silly) |
| backward(adjective, dull, simple, ability, slow) |
| bird-brained |