Strict church is over in force (7)
I believe the answer is:
precise
'strict' is the definition.
(thesaurus)
'church is over in force' is the wordplay.
'church' becomes 'CE' (abbreviation for Church of England).
'is over' says the letters should be written backwards.
'in' is an insertion indicator.
'force' becomes 'prise' (as in forcing or prising something open).
'ce' backwards is 'ec'.
'ec' placed inside 'prise' is 'PRECISE'.
(Other definitions for precise that I've seen before include "'Exact, accurate (7)'" , "Specific" , "with accuracy" , "Highly accurate and sharply exact" , "Express" .)