Representative of a man (5)
I believe the answer is:
agent
'representative' is the definition.
(agent is a kind of representative)
'a man' is the wordplay.
'man' becomes 'gent' (gent is a kind of man).
'a'+'gent'='AGENT'
'of' is the link.
(Other definitions for agent that I've seen before include "Operative" , "Factor, spy" , "Negotiator" , "One does business on behalf of another" , "Representative - means" .)