| impervious(adjective, obstinacy, impossibility) |
| implausible(adjective, doubtful, unlikely, impossible) |
| inaccessible(adjective, out, impossibility) |
| inadaptable(adjective, useless, unfit, inapplicable) |
| insuperable(adjective, unrealistic, impossibility) |
| intractable(adjective, difficulty, obstinacy) |
| inutile(adjective, weak, stupid, idle, useless) |
| invalid(adjective, useless, unfit, inapplicable) |
| reckless(adjective, foolish, crazy, irrational, outrageous) |
| refractory(difficulty, intractable) |
| ridiculous(adjective, silly, foolish, fantastic, unwise) |
| romantic(adjective, wild, unreasonable, useless, absurd) |
| unavailing(adjective, stupid, idle, useless, trivial) |
| unmanageable(adjective, difficulty, foolish, crazy, irrational) |
| unobtainable(adjective, impossible, impossibility) |
| unthinkable(adjective, possible) |
| vain(adjective, stupid, idle, useless, trivial) |
| bigoted(obstinacy, misjudgment) |
| bootless(adjective, stupid, idle, trivial, incompetent) |
| desperate(difficulty, impossibility) |