Communist machinery applying short shock to traitor (7)
I believe the answer is:
apparat
'communist machinery' is the definition.
I know nothing about this answer so I can't judge whether this works.
'short shock to traitor' is the wordplay.
'short' means to remove the last letter.
'shock' becomes 'appal' (synonyms).
'to traitor' becomes 'rat' (rat can mean a treacherous person).
'appal' with its last letter taken off is 'appa'.
'appa'+'rat'='APPARAT'
'applying' acts as a link.
Can you help me to learn more?
(Other definitions for apparat that I've seen before include "bureaucrats" , "communist group" , "Soviet system" , "Admin system of a communist party" , "Political machine" .)