European capital city
'european capital city' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for athens that I've seen before include "Plato's birthplace" , "Hasten to European city" , "Two thousand and four Olympics city" , "Mediterranean capital" , "Hasten to Greece" .)
(Other definitions for warsaw that I've seen before include "Largest city in Poland" , "Poland's largest city" , "Capital of a European Union state" , "Capital city on the Vistula" , "Capital city of Poland" .)
(Other definitions for rome that I've seen before include "When here, do as the citizens do" , "European capital" , "Basis for cheese" , "Where to emulate the locals" , "All roads lead to it" .)
(Other definitions for copenhagen that I've seen before include "European capital" , "Capital - Wellington's warhorse" , "below Wellington" , "Capital - battle won by 15" , "Duke of 21's horse at Waterloo -- capital city" .)