Deprive of food returning vermin with heartless violence (6)
I believe the answer is:
starve
'deprive of food' is the definition.
(synonyms)
'returning vermin with heartless violence' is the wordplay.
'returning' is a reversal indicator.
'vermin' becomes 'rats' (I've seen this before).
'with' is a charade indicator (letters next to each other).
'heartless' suggests removing the centre.
'violence' with its centre removed is 've'.
'rats' back-to-front is 'star'.
'star'+'ve'='STARVE'
(Other definitions for starve that I've seen before include "Suffer great hunger" , "Suffer from lack of food" , "Deprive of food" , "Averts (anag)" , "Become famished" .)