peace of mind vs ataraxis

peace of mind and ataraxis both are nouns.

Word	Noun	Adjective	Verb	Adverb
peace of mind	Yes	No	No	No
ataraxis	Yes	No	No	No

As nouns, peace of mind and ataraxis are synonyms defined as:

Other synonyms of peace of mind include heartsease, peace, peacefulness, repose, serenity.

peace of mind (noun)	ataraxis (noun)
the absence of mental stress or anxiety	the absence of mental stress or anxiety