Second worker shot (8)
I believe the answer is:
backhand
'shot' is the definition.
(type of shot in tennis)
'second worker' is the wordplay.
'second' becomes 'back' (to second a motion is to back it).
'worker' becomes 'hand' (hand is a kind of worker).
'back'+'hand'='BACKHAND'
(Other definitions for backhand that I've seen before include "tennis side" , "A racket stroke" , "flourish in court" , "shot from behind" , "stroke, in court" .)