Bishops, perhaps, beginning to discourage reform (4)
I believe the answer is:
mend
'reform' is the definition.
(thesaurus)
'bishops perhaps beginning to discourage' is the wordplay.
'bishops perhaps' becomes 'men' (bishop is a kind of man).
'beginning to' says to take the initial letters.
The first letter of 'discourage' is 'd'.
'men'+'d'='MEND'
(Other definitions for mend that I've seen before include "Put right" , "Return to health; repair" , "Make improvements" , "'Restore, fix (4)'" , "Heal" .)