A calm beyond perturbation: the settled, lucid untroubledness prized in Epicurean and skeptical philosophy, where desire is disciplined and fear (especially fear of death) is disarmed. Ataraxia is serenity earned, not numbness.

From Greek ataraxía "untroubledness," from a- "not" + tarassein "to disturb, trouble." The negative prefix works as method rather than void: remove the agitation, and clarity remains.