hmm, but Adios must surely be derived from "a Dios" and questioner said word, singular, which is why I originally said adios, then had doubts when I could not find the word on freetranslation. *and breathe*
This customary Spanish word for "good-bye" means "Go with God"...don't journey on by yourself...walk with God. The original Spanish phrase, "Vaya con Dios" was shortened to "Adios". At least according to Communicating in Latin America as well as my own experiences...