The Collaborative International Dictionary of English v.0.48:
acedia \acedia\ n. 1. apathy and inactivity in the practice of virtue (personified as one of the deadly sins). Syn: sloth, laziness [WordNet 1.5]WordNet (r) 3.0 (2006):
acedia n 1: apathy and inactivity in the practice of virtue (personified as one of the deadly sins) [syn: sloth, laziness, acedia]