Reveal a new grammatical term before church (8)
I believe the answer is:
announce
'reveal' is the definition.
(I've seen this before)
'a new grammatical term before church' is the wordplay.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'grammatical term' becomes 'noun' (type of word).
'before' is a charade indicator (letters next to each other).
'church' becomes 'CE' (Church of England).
'a'+'n'+'noun'+'ce'='ANNOUNCE'
(Other definitions for announce that I've seen before include "Tell everyone" , "say" , "Make known, declare" , "Reveal" , "Declare publicly" .)