Bill Clinton's third to imbibe a new wine (7)
I believe the answer is:
chianti
'wine' is the definition.
(I know that Chianti is a type of red wine)
'bill clinton's third to imbibe a new' is the wordplay.
'bill' becomes 'chit' (chit is a kind of bill).
'clinton's third' becomes 'i' (ird letter of 'clinton').
'to imbibe' is an insertion indicator (to imbibe can mean to drink or absorb).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'chit'+'i'='chiti'
'a'+'n'='an'
'chiti' going around 'an' is 'CHIANTI'.
(Other definitions for chianti that I've seen before include "Chain it to popular Italian wine" , "European wine" , "I can hit (anag) - alcoholic drink" , "Tuscan red wine" , "Popular dry red wine of Tuscany" .)