Crowd actor (5)
I believe the answer is:
extra
'crowd actor' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for extra that I've seen before include "lesser player" , "Additional, more than expected" , "Minor actor in crowd scene" , "comes to 16 [TEST MATCH]" , "Bye or wide, for example" .)