Domineering, ousting old King, offending the Church (7)
I believe the answer is:
impious
'offending the church' is the definition.
(impious means irreligious or ungodly)
'domineering ousting old king' is the wordplay.
'domineering' becomes 'imperious' (similar in meaning).
'ousting' suggests deleting specific letters.
'old king' becomes 'ER' (abbreviation for Edward Rex, various English kings).
'imperious' with 'er' removed is 'IMPIOUS'.
(Other definitions for impious that I've seen before include "Wicked, profane" , "Showing disrespect for a god" , "9 [DEMON]" , "Irreverent; wicked" , "Lacking veneration or respect" .)