Player is rubbish and about to be rejected (5)
I believe the answer is:
actor
'player' is the definition.
(synonyms)
'rubbish and about to be rejected' is the wordplay.
'rubbish' becomes 'rot' (both can mean nonsense).
'and' says to put letters next to each other.
'about' becomes 'ca' (circa).
'to be rejected' says the letters should be written in reverse.
'rot'+'ca'='rotca'
'rotca' in reverse letter order is 'ACTOR'.
'is' acts as a link.
(Other definitions for actor that I've seen before include "Stage-player" , "Theatre player" , "Croat (anag.)" , "Stage player" , "One on stage" .)