A state of listlessness, spiritual torpor, and restless indifference.
A state of listlessness, spiritual torpor, and restless indifference — an inability to care about one's condition, combining boredom with agitation rather than simple laziness.
The historical ancestor of the deadly sin of sloth, but richer: it is restless and agitated, not merely lazy. Heavier than secular ennui or boredom (it carries a spiritual loss of caring, even about the good), and unlike melancholy — which is sorrowful and can be pleasurable — acedia is an indifferent not-caring “that does not even care that it does not care.” Apathy is the closest secular synonym, minus the fidgety “noonday” restlessness.
Greek a- “without” + kēdos “care” = “not-caring.”
From Latin acēdia, from Greek akēdía “negligence, lack of care,” from a- “without” + kēdos “care, concern.”
Originally plain indifference in Greek; the desert monks gave it a spiritual tone — Evagrius of Pontus (4th c.) listed it among the eight evil “thoughts,” and John Cassian transmitted it to the Latin West as “the noonday demon.” In the medieval seven-deadly-sins scheme it was folded into sloth. The OED called accidie obsolete in 1933, but the word revived mid-20th century and is now often linked to depression and modern malaise.
The neat “acedia = depression” equation is partly modern projection; some scholars stress its distinctly spiritual, theological character. The line between acedia, tristitia (sadness), and sloth was already contested in antiquity.