Drunk chose to drink litres (7)
I believe the answer is:
pickled
'drunk' is the definition.
(I've seen this before)
'chose to drink litres' is the wordplay.
'chose' becomes 'picked' (picking is a kind of choosing).
'to drink' indicates putting letters inside.
'litres' becomes 'l'.
'picked' going around 'l' is 'PICKLED'.
(Other definitions for pickled that I've seen before include "Soused" , "Preserved in vinegar or brine" , "Preserved - drunk" , "Blotto" , "Drunk (as a gherkin?)" .)