A sort of ending? Bring back a medical practitioner (4)
I believe the answer is:
coda
'a sort of ending?' is the definition.
'back a medical practitioner' is the wordplay.
'back' is a reversal indicator.
'medical practitioner' becomes 'doc' (doc is a kind of medical practitioner).
'a'+'doc'='adoc'
'adoc' back-to-front is 'CODA'.
'bring' is the link.
(Other definitions for coda that I've seen before include "Musical finale" , "tail" , "Closing section of a musical composition" , "End piece written for a piece of music" , "Word that modifies" .)