| trial-and-error(adjective, new, trial, untried, preliminary) |
| trial and error(expression, idiom) |
| unconcluded(adjective, plain, new, bare, trial) |
| uneasy |
| unreliable(doubtful, vague, unsure) |
| vacillate |
| vicarious(extra, auxiliary, supernumerary) |
| watchful(adjective, careful, thoughtful, prudent, guarded) |
| watery(adjective, irresolute) |
| wavering(adjective, open, weak, uncertain, nervous) |
| dubious(adjective, open, uncertain, doubtful, vague) |
| wary(adjective, careful, vague, prudent, ambiguous) |
| abstract(adjective, vague, intellectual, logical, imaginary) |
| academic(adjective, uncertain, doubtful, vague, logical) |
| ad hoc |
| afraid(uncertain, nervous, shy, doubtful, hesitant) |
| agnostic(uncertain, hesitant, dubious, unsure) |
| alert(careful, thoughtful, prudent, watchful, guarded) |
| all ears(expression, careful, thoughtful, prudent, watchful) |
| amateurish |