One hope dashed involving the Italian connoisseur (9)
I believe the answer is:
oenophile
'connoisseur' is the definition.
(I've seen this before)
'one hope dashed involving the italian' is the wordplay.
'dashed' indicates anagramming the letters.
'involving' means one lot of letters goes inside another.
'the italian' becomes 'il' ('the' in Italian).
'one'+'hope'='onehope'
'onehope' anagrammed gives 'oenophe'.
'oenophe' enclosing 'il' is 'OENOPHILE'.
(Other definitions for oenophile that I've seen before include "port authority" , "wine I enjoy" , "Drink lover" , "Connoisseur of wine" , "Wine buff" .)