/ ˈkwestʃənəbl; NAmE / adjective
1.
that you have doubts about because you think it is not accurate or correct
SYN debatable :
The conclusions that they come to are highly questionable.
It is questionable whether this is a good way of solving the problem.
2.
likely to be dishonest or morally wrong
SYN suspect :
Her motives for helping are questionable.
► ques·tion·ably / -əbli; NAmE / adverb