It is 'questionable' whether this is the right decision. [=I question/doubt whether this is the right decision]
The water available in the village is of 'questionable' quality.
The truth of the statements was highly 'questionable'.
(..) Be thou a spirit of health or goblin damned... Bring with thee airs from heaven or blasts from hell... Be thy intents wicked or charitable... ...thou com'st in such a questionable shape that I will speak to thee I'll call thee Hamlet... King... Father... Royal Dane... Oh answer me! (..)2015 Hamlet