farewell vs going

farewell and going both are nouns.

Word	Noun	Adjective	Verb	Adverb
farewell	Yes	No	No	No
going	Yes	Yes	No	No

As nouns, going is a hypernym of farewell; that is, going is a word with a broader meaning than farewell:

Other hypernyms of farewell include departure, going away, leaving.

farewell (noun)	going (noun)
the act of departing politely	advancing toward a goal
an acknowledgment or expression of goodwill at parting	the act of departing
	euphemistic expressions for death

farewell (adjective)	going (adjective)
	in full operation