One used to groom hospital doctor superficially (9)
I believe the answer is:
hairbrush
'one' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for hairbrush that I've seen before include "It is used with a comb" , "It supplements comb for tidying tresses" , "Locks straightener" , "Personal grooming tool" , "Grooming aid" .)