A male representative (5)
I believe the answer is:
agent
'representative' is the definition.
(agent is a kind of representative)
'a male' is the wordplay.
'male' becomes 'gent' (gent is a kind of male).
'a'+'gent'='AGENT'
(Other definitions for agent that I've seen before include "Spy; service provider" , "Spy - broker" , "Author" , "Instrument" , "Catalyst" .)