Report a Catholic peer (7)
I believe the answer is:
account
'report' is the definition.
('account' can be a synonym of 'report')
'a catholic peer' is the wordplay.
'catholic' becomes 'c' (abbreviation as in RC for Roman Catholic).
'peer' becomes 'count'.
'a'+'c'+'count'='ACCOUNT'
(Other definitions for account that I've seen before include "Record of an event" , "Bill; importance" , "Bill; description" , "History" , "books" .)