Trespass as sin, a term including murder (11)
I believe the answer is:
assassinate
'murder' is the definition.
(thesaurus)
'trespass as sin a term including' is the wordplay.
'including' indicates the answer is hidden within the clue.
'ASSASSINATE' is hidden within 'trespass as sin a term'.
(Other definitions for assassinate that I've seen before include "Put an end to" , "Murder (a political or religious leader)" , "Kill by contract" , "Kill (a VIP)" , "Kill for a cause" .)