Parting; valedictory; final; as, a farewell discourse; his farewell bow.
source: Webster 1913
interjection
Go well; good-by; adieu; -- originally applied to a person departing, but by custom now applied both to those who depart and those who remain. It is often separated by the pronoun; as, fare you well; and is sometimes used as an expression of separation only; as, farewell the year; farewell, ye sweet groves; that is, I bid you farewell.
source: Webster 1913
noun
an acknowledgment or expression of goodwill at parting
source: WordNet 3.0
the act of departing politely
He disliked long farewells. He took his leave. Parting is such sweet sorrow.
source: WordNet 3.0
A wish of happiness or welfare at parting; the parting compliment; a good-by; adieu.