"Adios, ___!"
(Other definitions for amigo that I've seen before include "buddy abroad?" , "Foreign ally" , "Friend in Spanish-speaking area" , "Quixote's friend" , "Friend from Spain?" .)
'adios' is the definition.
(synonyms)
This is all the clue.
(Other definitions for bye that I've seen before include "I'm off" , "Cheerio" , "Cricketing extra" , "(Informal) valediction" , "Run scored in cricket from a ball that passes batman" .)
'adios' 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 "Italian cheerio" , "parting word" , "Italian greeting at meeting or parting" , "See you in Italy" , "European's greeting" .)
(Other definitions for tata that I've seen before include "So long!" , "See you" , "cheerio!" .)
(Other definitions for hasta la vista that I've seen before include "See you later" , "Until we meet again (Spanish)" , "Spanish farewell" .)