Sloth is one of the seven capital sins in Catholic teachings. The word "sloth" is a translation of the Latin term "acedia" (Middle English, "acciditties") and means "without care". Spiritually, "acedia" first referred to an affliction to women, religious persons, especially monks, wherein they became indifferent to their duties and obligations to God. Mentally, "acedia" has a number of distinctive components of which the most important is affectlessness, a lack of any feeling about self or other, a mind-state that gives rise to boredom, rancor, apathy, and a passive, inert, or sluggish mentation. Physically, "acedia" is fundamentally with a cessation of motion and an indifference to work; it finds expression in laziness, idleness, and indolence. Two commentators consider the most accurate translation of "acedia" to be "self-pity," for it "conveys both the melancholy of the condition and self-centeredness upon which it is founded."

Sloth ignores the seven gifts of grace given by the Holy Ghost (wisdom, understanding, counsel, knowledge, piety, fortitude, and fear of the Lord); such disregard slows spiritual progress towards life —- to neglect manifold duties of charity towards the neighbour, and animosity towards God.

Sloth has also been defined as a failure to do things that one should do. By this definition, evil exists when "good" people fail to act.

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