Meal not starting with reduced punch (8)
I believe the answer is:
uppercut
'punch' is the definition.
(I've seen this before)
'meal not starting with reduced' is the wordplay.
'meal' becomes 'supper' (supper is a kind of meal).
'not starting' means to remove the first letter.
'with' says to put letters next to each other.
'reduced' becomes 'cut' (similar in meaning).
'supper' with its initial letter removed is 'upper'.
'upper'+'cut'='UPPERCUT'
(Other definitions for uppercut that I've seen before include "Boxing blow delivered to chin from below" , "sock" , "Swinging blow from below aimed at an opponent's chin" , "Punch delivered vertically to chin" , "one must take it on the chin" .)