Tory accepts a new church law (5)
I believe the answer is:
canon
'church law' is the definition.
(I've seen this before)
'tory accepts a new' is the wordplay.
'tory' becomes 'con' (abbreviation for Conservative).
'accepts' means one lot of letters goes inside another.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'a'+'n'='an'
'con' going around 'an' is 'CANON'.
(Other definitions for canon that I've seen before include "accepted criterion" , "Member of the clergy" , "Cathedral cleric" , "Senior clergyman" , "Body of generally established principles for a given context" .)