Hasn't any choice new wine? (4)

I believe the answer is:

must

I'm a little stuck... Click here to teach me more about this clue!

'new wine?' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for must that I've seen before include "The mould is compelled" , "Mouldiness" , "Prerequisite" , "Mould - grape juice during fermentation" , "Make off with (plane)" .)

I've seen this clue in The Globe and Mail.

Want a hint initially instead of a full solution? Install my app