Light rabbit punch (3,4)
I believe the answer is:
gas lamp
'light' is the definition.
(gas lamp is a kind of light)
'rabbit punch' is the wordplay.
'rabbit' becomes 'gas' (I've seen this before).
'punch' becomes 'lamp' (lamp can informally mean to beat).
'gas'+'lamp'='GAS-LAMP'
(Other definitions for gas lamp that I've seen before include "Burning source of light" , "Form of illumination" , "may be illuminating" , "Pre-electric light" , "Victorian street light" .)