farewell vs acknowledgment

farewell and acknowledgment both are nouns.

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

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

Other hypernyms of farewell include acknowledgement.

farewell (noun)	acknowledgment (noun)
the act of departing politely	a statement acknowledging something or someone
an acknowledgment or expression of goodwill at parting	a short note recognizing a source of information or of a quoted passage
	the state or quality of being recognized or acknowledged