valediction vs leave-taking

valediction and leave-taking both are nouns.

Word	Noun	Adjective	Verb	Adverb
valediction	Yes	No	No	No
leave-taking	Yes	No	No	No

As nouns, leave-taking is a hypernym of valediction; that is, leave-taking is a word with a broader meaning than valediction:

Other hypernyms of valediction include farewell, leave, parting.

valediction (noun)	leave-taking (noun)
the act of saying farewell	the act of departing politely
a farewell oration (especially one delivered during graduation exercises by an outstanding member of a graduating class)