ataraxia vs serenity

ataraxia and serenity both are nouns.

Word	Noun	Adjective	Verb	Adverb
ataraxia	Yes	No	No	No
serenity	Yes	No	No	No

As nouns, serenity is a hypernym of ataraxia; that is, serenity is a word with a broader meaning than ataraxia:

Other hypernyms of ataraxia include placidity, quiet, repose, tranquility, tranquillity.

ataraxia (noun)	serenity (noun)
peace of mind	a disposition free from stress or emotion
	the absence of mental stress or anxiety