A leaden spiritual weariness. More than mere laziness, acedia is a sour, restless aversion to one's duties, one's place, even one's own life. It feels like fatigue that will not rest and boredom that will not lift. Where ennui remains secular, acedia has a moral and devotional sting: indifference as temptation.

From Greek akēdía "lack of care," from a- "not" + kēdos "care, concern." Early Christian ascetics wrote of it as the "noonday demon," the hour when prayer curdles into irritation and the mind hunts for escape. Later moral theology folded it into the genealogy of sloth, but the older word preserves the texture of the experience, a listlessness that feels like betrayal.