Sayonara is a farewell, borrowed from Japanese. Say sayonara, sayonara to all that, wave sayonara.
In English it is jaunty and often means good riddance, which is nothing like its weight in Japanese, where it is a fairly final goodbye that people avoid using with friends they expect to see again. The Japanese means roughly if that is how it is.
1nounsayonaraA farewell, borrowed from Japanese.
“He waved from the train window and shouted, "Sayonara, everyone!"”
sayonara is a farewell.
Japanese sayonara, literally if that is the way it is, shortened from a longer parting phrase.
Japanese
さようなら — farewell
English, today
sayonara
Borrowed from Japanese さようなら (“farewell”) literally “if that's the way it is” or its shorter, less traditional form さよなら.
Etymology from Wiktionary, CC BY-SA