What is the meaning of Acedia?

Spiritual or mental sloth and the feeling it provokes; apathy or indifference; a lack of care or interest and the resultant avoidance of duties; a bored melancholy leading to desperation, restlessness and anxiety.

acedia

sloth, torpor

ablative singular of acēdia

acedia (spiritual or mental sloth and the feeling it provokes; apathy or indifference; a lack of care or interest and the resultant avoidance of duties; a bored melancholy leading to desperation, restlessness and anxiety)

first/third-person singular imperfect indicative of aceder

Source: wiktionary.org