| questionable(adjective, weak, great, flat, poor) |
| remote(adjective, doubtful, dubious, unlikely, improbable) |
| ridiculous(adjective, keen, sharp, strange, crazy) |
| suspect(adjective, weak, extraordinary, amazing, likely) |
| thin(adjective, weak, great, poor, informal) |
| unimaginable(adjective, extraordinary, strange, amazing, doubtful) |
| unsubstantial(adjective, thin, extraordinary, strange, unreasonable) |
| ludicrous(adjective, strange, crazy, insane, absurd) |
| unsustainable |
| extreme(adjective, strange, crazy, insane, absurd) |
| illogical(adjective, poor, sense, fantastic, absurd) |
| problematic(adjective, likely, unlikely, unbelievable, improbable) |
| tall(adjective, hard, difficult, unreasonable, exaggerated) |
| beyond belief(expression, adjective, idiom, extraordinary, amazing) |
| crazy(adjective, strange, insane, absurd, excessive) |
| erratic(adjective, strange, crazy, insane, unpredictable) |
| unrealistic(adjective, strange, fantastic, doubtful, dubious) |
| untenable(adjective, irrational, unbelievable, improbable, unreasoned) |
| debatable |
| dubitable(adjective, improbable) |