Concupiscence (from Late Latin noun concupiscentia, from the Latin verb concupiscence, from con-, "with", here an intensifier, + cupi(d)-, "desiring" + -escere, a verb-forming suffix denoting beginning of a process or state) is an ardent, usually sensual, longing. In Christianity, particularly in Roman Catholic and Lutheran theology, concupiscence is the tendency of humans to sin.
There are nine occurrences of concupiscence in the Douay-Rheims Bible and three occurrences in the King James Bible. It is also one of the English translations of the Koine Greek epithumia (ἐπιθυμία), which occurs 38 times in the New Testament.
Involuntary sexual arousal is explored in the Confessions of Augustine, wherein he used the term "concupiscence" to refer to sinful lust.