Company doctor's groom (4)
I believe the answer is:
comb
'groom' is the definition.
(combing is a kind of grooming)
'company doctor's' is the wordplay.
'company' becomes 'co' (abbreviation).
'doctor' becomes 'mb' (Bachelor of Medicine, Medicinae Baccalaureus**).
'co'+'mb'='COMB'
(Other definitions for comb that I've seen before include "Groom the tresses" , "For use on hair" , "Fastening spikes" , "business storage unit" , "Toothed device - crest" .)