Female performer's agent (6)
I believe the answer is:
factor
'agent' is the definition.
(business term for a representative)
'female performer's' is the wordplay.
'female' becomes 'f' (abbreviation).
'performer' becomes 'actor' (actor is a kind of performer).
'f'+'actor'='FACTOR'
(Other definitions for factor that I've seen before include "one to be taken into account" , "Circumstance that contributes towards a result" , "Influencing circumstance" , "something that may affect result" , "Piece of information or element to be taken into account" .)