| strong |
| tricky(noun, adjective, delicate, false, loose) |
| troubled(uncertain, anxious, nervous, worried, hesitant) |
| uncomfortable |
| unconfirmed(doubtful, vague) |
| unfaithful(adjective, false, dishonest, deceitful, unpredictable) |
| unhealthy(adjective, delicate, uncertain, unstable, doubtful) |
| unsound(adjective, weak, loose, uncertain, unstable) |
| unspecified(adjective, rough, faint, vague, unknown) |
| unsteadfast |
| vacillate |
| variable(adjective, loose, uncertain, doubtful, vague) |
| whimsical |
| wimpy(adjective, weak, uncertain, nervous, doubtful) |
| wonky(adjective, unreliable, insecure, treacherous, incalculable) |
| yellow(adjective, irresolute) |
| lacking(adjective, poor, thin, uncertain, nervous) |
| lost(noun, uncertain, hesitant, dubious) |
| open to question(expression, adjective, idiom, dubious, shady) |
| accident-sensitive(adjective, unreliable, insecure, treacherous, incalculable) |