Norway's largest city (4)
I believe the answer is:
oslo
'norway's largest city' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for oslo that I've seen before include "Norway's capital city" , "European capital city (found in Czechoslovakia!)" , "Scandinavian city" , "Capital in throes of go-slow" , "European capital in go-slow" .)