Holy work restricting perversion of rites (8)
I believe the answer is:
priestly
'holy' is the definition.
(befitting a priest)
'work restricting perversion of rites' is the wordplay.
'work' becomes 'ply' (I've seen this in other clues).
'restricting' means one lot of letters goes inside another.
'perversion of' indicates anagramming the letters (a wrong or perverted order of letters).
'rites' is an anagram of 'riest'.
'ply' enclosing 'riest' is 'PRIESTLY'.
(Other definitions for priestly that I've seen before include "Ecclesiastical" , "Pious" , "Like a minister" , "just like a cleric" , "Hieratic" .)