| hesitant(uncertain, dubious, unsure) |
| hesitating(uncertain, hesitant, dubious, unsure) |
| high-flown(adjective, intellectual, supernatural, abstract, spiritual) |
| illogical(wild, unreasonable, useless, absurd, abstract) |
| illusory(fake, false, imaginary, unreal, fanciful) |
| imponderable(adjective, immaterial) |
| impossible(wild, silly, unreasonable, useless, absurd) |
| impracticable(wild, silly, unreasonable, useless, absurd) |
| improbable(wild, silly, unreasonable, useless, absurd) |
| in a quandary(expression, idiom, uncertain, hesitant, dubious) |
| in clouds(expression, uncertain, hesitant, dubious, unsure) |
| in dilemma(expression, uncertain, hesitant, dubious, unsure) |
| in the clouds(expression, adjective, idiom, intellectual, unreal) |
| inapplicable(wild, unreasonable, useless, absurd, abstract) |
| indecisive(uncertain, hesitant, dubious, unsure) |
| indefinite |
| indispensable(adjective, important, significant, original, essential) |
| inefficacious(wild, unreasonable, useless, absurd, abstract) |
| infeasible(wild, unreasonable, useless, absurd, unrealistic) |
| infinite(excellent, obscure, extraordinary, superior, fantastic) |