Posh daily located in most excellent city (9)
I believe the answer is:
bucharest
'city' is the definition.
(Bucharest is an example)
'posh daily located in most excellent' is the wordplay.
'posh' becomes 'u' (abbreviation for upper-class - opposite to non-U).
'daily' becomes 'char' (both can mean a cleaner).
'located in' is an insertion indicator.
'most excellent' becomes 'best' (the very best).
'u'+'char'='uchar'
'uchar' going into 'best' is 'BUCHAREST'.
(Other definitions for bucharest that I've seen before include "European city" , "Romanian capital" , "Capital of Romania" , "Balkan city" , "European capital" .)