Force to accept Church upset faithful (7)
I believe the answer is:
precise
'faithful' is the definition.
(thesaurus)
'force to accept church upset' is the wordplay.
'force' becomes 'prise' (I've seen this before**).
'to accept' is an insertion indicator.
'church' becomes 'ce' (abbreviation for Church of England).
'upset' is a reversal indicator.
'ce' in reverse letter order is 'ec'.
'prise' going around 'ec' is 'PRECISE'.
(Other definitions for precise that I've seen before include "Highly accurate and sharply exact" , "Express" , "Exact like recipes" , "'Exact, accurate (7)'" , "Detailed, exact" .)