Requests wine containers, unopened (4)
I believe the answer is:
asks
'requests' is the definition.
('ask' can be a synonym of 'request')
'wine containers unopened' is the wordplay.
'wine containers' becomes 'casks' (I've seen this in another clue).
'unopened' means to remove the first letter (the opening of the word is removed).
'casks' with its first letter taken off is 'ASKS'.
(Other definitions for asks that I've seen before include "Poses a question" , "Enquires; requests" , "Demands (something of someone)" , "Inquiries" , "is curious" .)