Quote Italian in Church (4)
I believe the answer is:
cite
'quote' is the definition.
('cite' can be a synonym of 'quote')
'italian in church' is the wordplay.
'italian' becomes 'it'.
'in' indicates putting letters inside.
'church' becomes 'ce' (abbreviation for Church of England).
'it' inserted inside 'ce' is 'CITE'.
(Other definitions for cite that I've seen before include "Quote (a reference)" , "Quote (an author)" , "for instance" , "Quote (eg, a book)" , "Summons - quote" .)