Listlessness, depression, or a spiritual ennui [can] appear in place of one's former enthusiasm, and one comes ever closer to abandoning the journey. The vice was so common in fourth century hermitages that the early Christian monks had a name for it: accidie (or accidia). In early monastic literature accidie is often depicted as a temptation of the early afternoon. By midday one's stamina wanes even though the evening's rest remains far away. One is vulnerable and easily discouraged. This, of course, is metaphor. While accidie may occur during the course of a single day, it may also visit us at any of those points on the inward journey at which we feel weary or especially tender. Yet even as accidie signals danger, it can also signal the advent of God's grace.
— William A. Simpson, From Image To Likeness