Farewell in Firenze (4)
I believe the answer is:
ciao
'farewell in firenze' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ciao that I've seen before include "Italian hello or goodbye" , "Italian hello-goodbye" , "Hi - bye" , "See you later in Rome?" , "See you in Italy" .)