Guilty party's rip-off concealed by religious group (7)
I believe the answer is:
culprit
'guilty party's' is the definition.
(I've seen this before)
'rip-off concealed by religious group' is the wordplay.
'off' is an anagram indicator.
'concealed by' means one lot of letters goes inside another.
'religious group' becomes 'cult' (I've seen this before).
'rip' anagrammed gives 'pri'.
'pri' going inside 'cult' is 'CULPRIT'.
(Other definitions for culprit that I've seen before include "Criminal" , "he should have conviction" , "baddie" , "Person responsible for wrongdoing" , "The one to blame, guilty party" .)