ataraxia

n. calm, freedom from worry, tranquility

Ataraxia (Ἀταραξία) is a Greek term used by Pyrrho and Epicurus for freedom from worry or any other preoccupation, and for Epicurus to achieve Hêdonê, the great pleasure. For the Stoics, ataraxia was synonymous with the only true happiness possible for a person. It signifies the detached and balanced state of mind that shows that a person has transcended the material world and is now harvesting all the comforts of philosophy.
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Noun
1. peace of mind
(hypernym) repose, quiet, placidity, serenity, tranquillity, tranquility

n. ataraxia

(n.)
Alt. of Ataraxy