Is inclined to enter the Church subject to purification (7)
I believe the answer is:
cleanse
'subject to purification' is the definition.
(I've seen this before)
'is inclined to enter the church' is the wordplay.
'is inclined' becomes 'leans' ('lean' can be a synonym of 'be inclined').
'to enter' means one lot of letters goes inside another.
'the church' becomes 'CE' (Church of England).
'leans' put inside 'ce' is 'CLEANSE'.
(Other definitions for cleanse that I've seen before include "Wash" , "Disinfect" , "Free of sin" , "Make free from dirt" , "Scrub" .)