Boxing punch (8)
I believe the answer is:
uppercut
'boxing punch' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for uppercut that I've seen before include "Swinging blow in boxing" , "Punch to opponent's chin from below" , "Swinging blow from below aimed at an opponent's chin" , "Boxer's blow" , "Boxing blow delivered to chin from below" .)