Surplus actor in small role (5)
I believe the answer is:
extra
This could be a double definition.
'surplus' is the first definition.
(synonyms)
'actor in small role' is the second definition.
'extra' can be an answer for 'actor' (extra is a type of actor). I am not certain of the 'in small role' bit.
Can you help me to learn more?
(Other definitions for extra that I've seen before include "Minor actor in crowd scene" , "Auxiliary" , "Bit player in film" , "late edition" , "redundant > spear-carrier" .)