Sophisticated old city facing plague (6)
I believe the answer is:
urbane
'sophisticated' is the definition.
(synonyms)
'old city facing plague' is the wordplay.
'old city' becomes 'ur' (ancient city state).
'facing' says to put letters next to each other.
'plague' becomes 'bane'.
'ur'+'bane'='URBANE'
(Other definitions for urbane that I've seen before include "Sophisticated and elegant - sounds citified" , "Smooth" , "Cosmopolitan" , "Cultured" , "Refined and civilised" .)