| inconclusive(adjective, clear, certain, shaky, unlikely) |
| incredible(adjective, unreasonable, doubtful, dubious, suspicious) |
| insecure(adjective, delicate, uncertain, nervous, unstable) |
| irresolute(adjective, uncertain, nervous, doubtful, insecure) |
| knobbed |
| mootable(adjective, certain, uncertain, doubtful, dubious) |
| open to doubt(expression, idiom, uncertain, doubtful, dubious) |
| paradoxical |
| problem(adjective, tough, severe, grim, painful) |
| puzzled |
| questioned |
| recondite(adjective, hard, fancy, difficult, complex) |
| ridiculous(adjective, doubtful, dubious, suspicious) |
| slippery(adjective, delicate, uncertain, unstable, doubtful) |
| speculative(shaky, vague, risky, imaginary, unlikely) |
| thick(adjective, doubtful, dubious, suspicious) |
| thin(adjective, unreasonable, doubtful, dubious, suspicious) |
| titanic(tough, severe, painful, trying) |
| tortuous |
| touch and go(expression, adjective, idiom, delicate, uncertain) |