A setter having a drink, raises a question (6)
I believe the answer is:
enigma
'a question' is the definition.
(enigma is a kind of question)
'a setter having a drink raises' is the wordplay.
'setter' becomes 'me' (the setter of the clue).
'having' indicates putting letters inside.
'a drink' becomes 'gin' (gin is a kind of drink).
'raises' says the letters should be written backwards.
'a'+'me'='ame'
'ame' placed around 'gin' is 'amgine'.
'amgine' in reverse letter order is 'ENIGMA'.
(Other definitions for enigma that I've seen before include "WW two Ger. code device; puzzle" , "'Puzzle, riddle (6)'" , "Gamine being a bit of a puzzle" , "Title of Elgar's set of variations" , "Mysterious puzzle" .)