Newsboy's shout (5)
I believe the answer is:
extra
'newsboy's shout' 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 "Not a hit certainly" , "Actor in crowd scene, no lines" , "leg bye perhaps" , "appearing in crowd scene" , "Ancillary" .)