Waterproof cloth (7)
I believe the answer is:
oilskin
'waterproof cloth' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for oilskin that I've seen before include "protective cover" , "Heavy-duty waterproof" , "protection for Ainslie?" , "Raincoat" , "Waterproof fabric" .)