A question that's full of holes? (6)
I believe the answer is:
riddle
'a question' is the definition.
(riddle is a kind of question)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for riddle that I've seen before include "Question to test ingenuity, something puzzling" , "unsolved problem" , "Sieve or conundrum" , "it's full of holes" , "It may have an answer" .)