It's southwest of Bologna (4)
I believe the answer is:
pisa
'it's southwest of bologna' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pisa that I've seen before include "City in Tuscany" , "Site of the famous leaning tower" , "Place with leaning tower" , "City on the River Arno" , "Italian city with famous tower" .)