Paint oil (7)
I believe the answer is:
linseed
'paint oil' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for linseed that I've seen before include "Oil produced from flax" , "Source of plant oil" , "Treatment for bats" , "Enisled (anag.)" , "Flax plant product providing oil" .)