Despondency (laziness), (Latin tristitia or acedia, "carelessness") refers to a set of concepts dating back to antiquity and including mental, spiritual, pathological and physical conditions. This complex can be defined as a lack of interest or habitual unwillingness to make efforts.
In his Summa Theologica, St. Thomas Aquinas defined idleness as "sorrow for spiritual good."
The general relaxation of mental and bodily forces, combined with extreme pessimism, is considered to be despondency. But it is important to understand that despondency occurs in a person due to a deep mismatch of the abilities of his soul, jealousy (emotionally colored desire for action) and will.
In the ordinary state, the will determines for a person the goal of his aspirations, and zeal is the "motor" that allows him to move towards it, overcoming difficulties. In case of despondency, a person directs jealousy to his current state, far from the goal, and the will, left without an "engine", turns into a constant source of longing for unfulfilled plans. These two forces of a discouraged person, instead of moving towards the goal, seem to "pull" his soul in different directions, bringing it to complete exhaustion.
Such inconsistency is the result of man's falling away from God, a tragic consequence of the attempt to direct all the forces of his soul to earthly things and joys, while they were given to us to strive for heavenly joys.