Socialist actors run out (6)
I believe the answer is:
castro
'socialist' is the definition.
(Fidel Castro, former president of Cuba)
'actors run out' is the wordplay.
'actors' becomes 'cast' (group of actors).
'run out' becomes 'RO' (cricket abbreviation).
'cast'+'ro'='CASTRO'
(Other definitions for castro that I've seen before include "Cuban dictator" , "Actors in Cuba" , "Old leader" , "Cuban co-star" , "Fidel -, former Cuban leader" .)