Something is questionable if people have doubts about its truth or value.
When we say that something is questionable, we usually mean that there's not enough evidence to make a firm decision. For example, let's say someone claims to have made a fortune investing in a new business, but others think they might be exaggerating. Their story could be called questionable because it sounds too good (or bad) to be true. You might also use this word when you're discussing a law or rule that seems unfair, but whose fairness is hard to prove. Maybe there are some loopholes or biases involved that make the situation questionable.
Problematic; open to doubt or challenge.
Example: It is questionable if the universe is open or closed.
