Clocking out (8)
I believe the answer is:
striking
This clue is a double definition.
'clocking' is the first definition.
(clock can mean to hit or strike)
'out' is the second definition.
(I've seen this before)
(Other definitions for striking that I've seen before include "not working" , "going like the clappers?" , "Delivering a blow" , "Hitting or refusing to work" , "Attracting attention by reason of being unusual" .)