Preserved in vinegar (7)
I believe the answer is:
pickled
'preserved in vinegar' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for pickled that I've seen before include "Drunk (as a gherkin?)" , "Preserved in liquid" , "Brahms and Liszt" , "Soused" , "Blotto" .)