No contest! Plain stupid old city (14)
I believe the answer is:
constantinople
'old city' is the definition.
(I've seen this before)
'no contest plain stupid' is the wordplay.
'stupid' indicates anagramming the letters (in a stupid order).
'no'+'contest'+'plain'='nocontestplain'
'nocontestplain' is an anagram of 'CONSTANTINOPLE'.
(Other definitions for constantinople that I've seen before include "Istanbul formerly" , "place that changed its name" , "seat for emperor" , "Old name of Istanbul" , "Former name of Istanbul" .)