Somehow halts urge to kill (9)
I believe the answer is:
slaughter
'kill' is the definition.
(I know that slaughter is a more specific form of the action kill)
'somehow halts urge' is the wordplay.
'somehow' indicates an anagram.
'halts'+'urge'='haltsurge'
'haltsurge' anagrammed gives 'SLAUGHTER'.
'to' is the link.
(Other definitions for slaughter that I've seen before include "Murder" , "Glare thus to cause bloodthirsty killing" , "Massacre" , "in which many die" , "Mass killing or carnage" .)