Unfriendly party at ancient city (4)
I believe the answer is:
dour
'unfriendly' is the definition.
(thesaurus)
'party at ancient city' is the wordplay.
'party' becomes 'do' (do is a kind of party).
'at' is a charade indicator (letters next to each other).
'ancient city' becomes 'ur' (ancient Sumerian city state).
'do'+'ur'='DOUR'
(Other definitions for dour that I've seen before include "Gloomy-looking and forbidding" , "Sullen - unyielding" , "Gloomy-looking, stern" , "Lugubrious, grim" , "Grim and gloomy-looking" .)