Fat extracted from wool (7)
I believe the answer is:
lanolin
'fat extracted from wool' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for lanolin that I've seen before include "Oil on sheep's wool" , "Substance found on sheep's wool" , "Grease on sheep's wool" , "Wool fat used in ointments" , "Oily substance on wool" .)