Retire, leaving a northern Italian city (5)
I believe the answer is:
turin
'italian city' is the definition.
(I've seen this before)
'retire leaving a northern' is the wordplay.
'retire' becomes 'turnin' ('turn in' can be a synonym of 'retire').
'leaving' suggests deleting specific letters.
'a northern' becomes 'n' (abbreviation e.g. N. Ireland).
'turnin' with 'n' taken out is 'TURIN'.
(Other definitions for turin that I've seen before include "N. Italian industrial city" , "City of northwest Italy (with a shroud)" , "foreign city" , "NW Italian city with famous Shroud" , "North Italian city" .)