It's a west-facing wine-producing area (4)
I believe the answer is:
asti
'wine-producing area' is the definition.
(area of Italy)
'it's a west-facing' is the wordplay.
'west-facing' says the letters should be written in reverse (letters written right to left or east to west).
'its'+'a'='itsa'
'itsa' back-to-front is 'ASTI'.
(Other definitions for asti that I've seen before include "Italian product" , "Italian town, famous for its wine" , "town in Italy" , "Fizzy wine" , "Italian white wine" .)