Villain heading off for part of church (4)
I believe the answer is:
nave
'part of church' is the definition.
('nave' is part of 'church')
'villain heading off' is the wordplay.
'villain' becomes 'knave' (knave is a kind of villain).
'heading off' means to remove the first letter.
'knave' with its initial letter taken off is 'NAVE'.
'for' is the link.
(Other definitions for nave that I've seen before include "Central part of church" , "Main part of a church" , "Central area in a church" , "Central space in church" , "Central place in church" .)