Wine in box with lid off upended (7)
I believe the answer is:
retsina
'wine' is the definition.
(type of Greek wine)
'in box with lid off upended' is the wordplay.
I cannot really see how this works, but
'in' is found in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for retsina that I've seen before include "Greek drink" , "Oily-tasting Greek white wine" , "Greek white wine flavoured with resin" , "Greek wine - nastier sort" , "Nastier (anag) - Greek wine" .)