| daffy(weak, simple, silly, foolish, thoughtless) |
| daft(weak, simple, silly, foolish, thoughtless) |
| daring(careless, wild, dirty, foul, improper) |
| deceived(adjective, foolish, unreasonable, unwise, mistaken) |
| determined(careless, thoughtless, impulsive, reckless, hasty) |
| dippy(weak, simple, silly, foolish, thoughtless) |
| disinformed(adjective, foolish, unreasonable, unwise, mistaken) |
| doltish(dull, weak, simple, silly, foolish) |
| dotty(weak, simple, silly, foolish, thoughtless) |
| dumb(dull, impulsive, impractical, unintelligent, half-baked) |
| erroneous(adjective, foolish, unreasonable, unwise, mistaken) |
| faked-out(adjective, foolish, unreasonable, unwise, mistaken) |
| fantastic(weak, simple, silly, foolish, thoughtless) |
| fast-and-loose(adjective, careless, bold, thoughtless, impulsive) |
| featherheaded |
| feebleminded(weak, simple, silly, foolish, thoughtless) |
| fiery(careless, thoughtless, impulsive, reckless, hasty) |
| flashy(adjective, offensive, rude, foolish, stupid) |
| flippancy |
| flippant(adjective, talkative, garrulous, mouthy, blithering) |