It wasn't built in a day (4)
I believe the answer is:
rome
'it wasn't built in a day' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rome that I've seen before include "Spanish Steps city" , "When there, do as the native do" , "Basis for cheese" , "All roads lead to it" , "City not built in a day" .)