Insubordination of man’s desires to the dictates of reason, and the propensity of human nature to sin as a result of original sin.

More commonly, concupiscence is spontaneous movement of the sensitive appetites toward whatever the imagination portrays as pleasant, and away from whatever it portrays as painful.

Concupiscence also includes unruly desires of the will, such as pride, ambition, and envy.

There are two particular cases of concupiscence:

Concupiscence of the eyes is unwholesome curiosity, an unreasonable desire to see, hear and know what is harmful to our virtue, inconsistent with our state of life, or detrimental to higher duties. It is also inordinate love of the world’s goods, the desire to acquire material possessions by any means necessary, to satisfy our ambitions, or nurture our pride.

Concupiscence of the flesh is an inordinate love of sensual pleasure, to which fallen man is naturally prone. It is inordinate when pleasure is pursued as an end in itself. Its divinely intended purpose is to facilitate the practice of virtue and satisfy our legitimate desires.