| implausible(doubtful, unlikely) |
| impracticable(doubtful, unlikely, implausible) |
| in the background(expression, idiom, isolated, reclusive, uncompanionable) |
| in the boonies(expression, idiom, isolated, reclusive, uncompanionable) |
| in the distance(expression, idiom, isolated, reclusive, uncompanionable) |
| in the sticks(expression, idiom, isolated, reclusive, uncompanionable) |
| incapacious |
| incog(strange, indefinite, unidentified) |
| incogitable(adjective, belief, impossible, inconceivable) |
| incognito(strange, indefinite, unidentified) |
| incommunicado(isolated, reclusive, uncompanionable) |
| incomparable(unusual, special, rare) |
| incredible(extraordinary, unusual, wonderful, exceptional, doubtful) |
| indefinite(strange, unidentified) |
| inexperienced(odd, bizarre, outlandish) |
| inexplainable(adjective, supernormal) |
| infrequent(unusual, special, rare, scarce, uncustomary) |
| inimitable(unusual, special, rare) |
| insular(isolated, reclusive, uncompanionable) |
| insupposable(adjective, belief, impossible, inconceivable) |