Cautious about girl serving wine (10)
I believe the answer is:
chardonnay
'wine' is the definition.
(I know that Chardonnay is a type of white wine)
'cautious about girl' is the wordplay.
'cautious' becomes 'chary' (similar in meaning).
'about' is an insertion indicator.
'girl' becomes 'donna' ().
'chary' enclosing 'donna' is 'CHARDONNAY'.
'serving' acts as a link.
(Other definitions for chardonnay that I've seen before include "drink" , "White wine grape" , "Variety of white wine" .)