Knock back a small drink in Italy (4)
I believe the answer is:
pisa
'in italy' is the definition.
('Pisa' is part of 'italy')
'knock back a small drink' is the wordplay.
'knock back' is a reversal indicator.
'small drink' becomes 'sip' (I've seen this in another clue).
'a'+'sip'='asip'
'asip' backwards is 'PISA'.
(Other definitions for pisa that I've seen before include "Site of the famous leaning tower" , "Italian city with famous tower" , "listed building site" , "Italian city with leaning tower" , "Place with leaning tower" .)