Coffee and brief conversation with doctor (5)
I believe the answer is:
mocha
'coffee' is the definition.
(mocha is a kind of coffee)
'brief conversation with doctor' is the wordplay.
'brief' means to remove the last letter.
'conversation' becomes 'chat' (chat is a kind of conversation).
'with' says to put letters next to each other.
'doctor' becomes 'mo' (medical officer**).
'chat' with its final letter taken away is 'cha'.
'cha' put after 'mo' is 'MOCHA'.
'and' acts as a link.
(Other definitions for mocha that I've seen before include "Coffee flavour" , "Strong dark coffee" , "Kid" , "Macho (anag.); coffee with chocolate" , "Coffee drink" .)