Struggle to get a doctor into a coat (6)
I believe the answer is:
combat
'struggle' is the definition.
(combating is a kind of struggling)
'a doctor into a coat' is the wordplay.
'a doctor' becomes 'mb' (Bachelor of Medicine, Medicinae Baccalaureus).
'into' is an insertion indicator.
'mb' placed into 'coat' is 'COMBAT'.
'to get' is the link.
(Other definitions for combat that I've seen before include "Military fighting" , "sort of jacket" , "A fight or contest, sometimes mortal" , "Military action" , "Fight against; fighting" .)