Light punch (4)
I believe the answer is:
lamp
I believe this is a double definition.
'light' is the first definition.
(lamp is a kind of light)
'punch' is the second definition.
(I've seen this before)
(Other definitions for lamp that I've seen before include "Device providing illumination" , "Aladdin's - -" , "Source of artificial light" , "punch" , "Device for giving light on palm" .)