farewell vs acknowledgement

farewell and acknowledgement both are nouns.

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

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

Other hypernyms of farewell include acknowledgment.

farewell (noun)	acknowledgement (noun)
the act of departing politely	a statement acknowledging something or someone
an acknowledgment or expression of goodwill at parting	the state or quality of being recognized or acknowledged