Shed, throw off (4)
I believe the answer is:
cast
This clue is a double definition.
'shed' is the first definition.
(shed can mean to discard or cast off)
'throw off' is the second definition.
(synonyms)
(Other definitions for cast that I've seen before include "Mould; actors in a play" , "Play's actors" , "The acting complement of a play" , "Set of performers" , "Discard; mould" .)