Performers cast or sacked (6)
I believe the answer is:
actors
'performers' is the definition.
(actor is a kind of performer)
'cast or sacked' is the wordplay.
'sacked' is an anagram indicator.
'cast'+'or'='castor'
'castor' anagrammed gives 'ACTORS'.
(Other definitions for actors that I've seen before include "Thespians" , "eg 9 & 11 across" , "Cast" , "Theatrical performers" , "The Gleeson boys, say" .)