| iffy(adjective, uncertain, doubtful, shaky, likely) |
| impracticable(adjective, wild, silly, unreasonable, doubtful) |
| incomprehensible(adjective, awful, strange, wonderful, fabulous) |
| infeasible(wild, unreasonable, useless, absurd, unrealistic) |
| legendary(adjective, mythical, fabled, mythological) |
| mysterious |
| outside |
| paradoxical |
| problematic(adjective, uncertain, unreasonable, doubtful, shaky) |
| shady(uncertain, doubtful, shaky, unsure, unlikely) |
| shaky(adjective, likely, unlikely, unpromising) |
| strained |
| suspect(extraordinary, uncertain, unreasonable, doubtful, dubious) |
| suspicious(uncertain, fantastic, doubtful, unsure, unbelievable) |
| unapt(adjective, doubtful, likely) |
| unattainable(wild, unreasonable, useless, absurd, unrealistic) |
| unconceivable(adjective, likely, implausible) |
| unfeasible(wild, unreasonable, useless, absurd, unrealistic) |
| unreal(adjective, wild, unreasonable, absurd, abstract) |
| unusable(adjective, wild, unreasonable, useless, absurd) |