Doctor's enemy having drink in Denmark (5)
I believe the answer is:
dalek
'doctor's enemy' is the definition.
'dalek' can be an answer for 'enemy' (I have seen 'Alien enemy' mean 'dalek' so perhaps 'enemy' could also mean 'dalek'). I am not sure about the 'doctor's' bit.
'drink in denmark' is the wordplay.
'drink' becomes 'ale' (type of beer).
'in' is an insertion indicator.
'denmark' becomes 'dk'.
'ale' inserted within 'dk' is 'DALEK'.
'having' acts as a link.
Can you help me to learn more?
(Other definitions for dalek that I've seen before include "Doctor Who adversary" , "Hostile alien" , "Sci-fi robot" , "Croaky-voiced exterminator" , "Doctor Who enemy" .)