Render unconscious, packing English weapon (4,3)
I believe the answer is:
sten gun
'weapon' is the definition.
(I've seen this before)
'render unconscious packing english' is the wordplay.
'render unconscious' becomes 'stun' (I've seen this before).
'packing' is an insertion indicator (some letters are packed inside).
'english' becomes 'eng' (abbreviation).
'stun' placed around 'eng' is 'STEN GUN'.
(Other definitions for sten gun that I've seen before include "weapon" , "One fires" , "Killer" .)