Rob's cut and run before church (6)
I believe the answer is:
fleece
'rob's' is the definition.
('fleece' can be a synonym of 'rob')
'cut and run before church' is the wordplay.
'cut and run' becomes 'flee' (I've seen this before).
'before' says to put letters next to each other.
'church' becomes 'ce' (abbreviation for Church of England**).
'flee'+'ce'='FLEECE'
(Other definitions for fleece that I've seen before include "Outer coat of sheep" , "Rob by trickery, say sheep" , "Swindle - wool removed from sheep" , "thermal garment" , "Woollen coat of sheep" .)