| unclear(uncertain, doubtful, shaky, unsure, unlikely) |
| uncommon |
| unconfirmed(uncertain, shaky, unclear, unlikely, questionable) |
| unconvinced(uncertain, doubtful, unsure) |
| undecided(uncertain, doubtful, unclear, unsure, questionable) |
| undependable(uncertain, doubtful, unsure) |
| uneasy(uncertain, shaky, unclear, unlikely, questionable) |
| unexplored(experience, distant, different, unfamiliar, external) |
| unfamiliar(experience, distant, different, external, foreign) |
| unheard of(expression, doubtful, unlikely, implausible) |
| unknown(experience, distant, different, unfamiliar, external) |
| unnatural(adjective, hard) |
| unreal(adjective, fantastic, imaginary, unlikely, unbelievable) |
| unreliable(uncertain, doubtful, unsure) |
| unstable(uncertain, shaky, unclear, unlikely, questionable) |
| unsubstantial(extraordinary, amazing, doubtful, unlikely, implausible) |
| unsure(uncertain, doubtful, unclear, questionable) |
| untrustworthy(uncertain, doubtful, unsure) |
| untrusty(uncertain, doubtful, unsure) |
| unusual |