Greek character's dropped off French wine for trainee (5)
I believe the answer is:
cadet
'trainee' is the definition.
(cadet is a kind of trainee)
'greek character's dropped off french wine' is the wordplay.
'greek character's' becomes 'mus' (mu is a Greek letter).
'dropped off' suggests deleting specific letters.
'french wine' becomes 'muscadet'.
'muscadet' with 'mus' removed is 'CADET'.
'for' is the link.
(Other definitions for cadet that I've seen before include "young soldier" , "Trainee -- acted (anag)" , "who needs to be properly trained?" , "Tomboy" , "Trainee cop" .)