Smell coming from party in old, old city (5)
I believe the answer is:
odour
'smell' is the definition.
('odour' can be a synonym of 'smell')
'party in old old city' is the wordplay.
'party' becomes 'do' (do is a kind of party).
'in' means one lot of letters goes inside another.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'old city' becomes 'ur' (ancient city state).
'o'+'ur'='our'
'do' put within 'our' is 'ODOUR'.
'coming from' is the link.
(Other definitions for odour that I've seen before include "Pong" , "Olfactory sensation" , "Perfume" , "Smell; repute" , "Stink" .)