Film actor quietly leaving (5)
I believe the answer is:
layer
'film' is the definition.
(film can mean a thin layer of something)
'actor quietly leaving' is the wordplay.
'actor' becomes 'player' (synonyms).
'quietly' becomes 'p' (musical symbol).
'leaving' is a deletion indicator.
'player' with 'p' taken out is 'LAYER'.
(Other definitions for layer that I've seen before include "Thickness of material or earth - relay it" , "Film" , "Tier or thickness - or a hen?" , "plate?" , "course" .)