"Arrivederci!” (4)
(Other definitions for roma that I've seen before include "Travellers, gypsies" , "Italian Rome" , "Members of a nomadic people" , "Travelling people" , "Travellers; Italian capital" .)
'arrivederci' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ciao that I've seen before include "European greeting" , "Italian cheerio" , "Italian greeting at meeting or parting" , "Italian salutation" , "See you later in Rome?" .)