| immature(careless, thoughtless, impulsive, reckless, negligent) |
| impatient(adjective, careless, quick, impulsive, reckless) |
| impolite(adjective, sharp, rude, indifferent, short) |
| imprudence |
| impudent |
| inappropriate(foolish, thoughtless, unwise, risky, imprudent) |
| incautiousness |
| indifferent(rude, casual, unkind, impolite, inconsiderate) |
| insolent |
| insuppressible(careless, thoughtless, impulsive, reckless, hasty) |
| intrepid |
| irrational(adjective, weak, simple, careless, silly) |
| jerky(weak, simple, silly, foolish, thoughtless) |
| jumping to conclusions(expression, idiom, careless, thoughtless, impulsive) |
| kooky(weak, simple, wild, silly, foolish) |
| lax(careless, casual, thoughtless, reckless, negligent) |
| loony(weak, simple, silly, foolish, thoughtless) |
| loose(careless, casual, thoughtless, reckless, negligent) |
| ludicrous(weak, simple, silly, foolish, thoughtless) |
| lunatic(weak, simple, silly, foolish, thoughtless) |