Actor's coat put on peg, initially (6)
I believe the answer is:
player
'actor's' is the definition.
('player' can be a synonym of 'actor')
'coat put on peg initially' is the wordplay.
'coat' becomes 'layer' (layering is a kind of coating).
'put on peg' becomes 'p' (I am not sure about this - if you are sure you should believe this answer much more).
'initially' means one lot of letters go next to another.
'layer' put after 'p' is 'PLAYER'.
Can you help me to learn more?
(Other definitions for player that I've seen before include "Sportsman - instrumentalist" , "Actor - musician" , "Competitor; musician" , "Participant in competitive game" , "Actor - footballer?" .)