arrivederci
/arˈviːdɛr.tʃi/Definitions
1. noun
A formal or polite way of saying goodbye, especially when parting with someone for a long time or permanently.
“The friends shared a tender arrivederci at the airport, knowing it might be years before they saw each other again.”
2. interjection
Used to bid a formal or polite farewell.
“Arrivederci, and may fortune smile upon you on your travels!”