tranquility vs ataraxis

tranquility and ataraxis both are nouns.

Word	Noun	Adjective	Verb	Adverb
tranquility	Yes	No	No	No
ataraxis	Yes	No	No	No

As nouns, ataraxis is a hyponym of tranquility; that is, ataraxis is a word with a more specific, narrower meaning than tranquility:

Other hyponyms of tranquility include heartsease, peace, peace of mind, peacefulness, repose, serenity, easiness, relaxation.

tranquility (noun)	ataraxis (noun)
a disposition free from stress or emotion	the absence of mental stress or anxiety
a state of peace and quiet
an untroubled state; free from disturbances