Blooming group of actors is rejected (7)
I believe the answer is:
outcast
'is rejected' is the definition.
(I've seen this before)
'blooming group of actors' is the wordplay.
'blooming' becomes 'out' (plants which have bloomed are 'out').
'group of actors' becomes 'cast' (group of actors in a production).
'out'+'cast'='OUTCAST'
(Other definitions for outcast that I've seen before include "One is excluded from society" , "One has been rejected by friends or society" , "one's not admitted" , "Displaced person" , "Discarded" .)