A number will enjoy the thing in question (5)
I believe the answer is:
digit
'a number' is the definition.
(digit is a kind of number)
'will enjoy the thing in question' is the wordplay.
'will' is a charade indicator (letters next to each other) (I've seen this in other clues).
'enjoy' becomes 'dig' (to dig can mean to appreciate or 'get').
'the thing in question' becomes 'it' (I am not sure about this - if you are sure you should believe this answer much more).
'dig'+'it' is 'DIGIT'.
Can you help me to learn more?
(Other definitions for digit that I've seen before include "one's given?" , "Single figure - finger" , "E.g. toe" , "Finger; number" , "One in ten, say" .)