Spy American man of refined manners (5)
I believe the answer is:
agent
'spy' is the definition.
(thesaurus)
'american man of refined manners' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'man of refined manners' becomes 'gent'.
'a'+'gent'='AGENT'
(Other definitions for agent that I've seen before include "Representative - means" , "Author" , "Spy - broker" , "Business manager" , "Delegate" .)