Catechism:
2515 Etymologically, “concupiscence” can refer to any intense form of human desire. Christian theology has given it a particular meaning: the movement of the sensitive appetite contrary to the operation of the human reason. The apostle St. Paul identifies it with the rebellion of the “flesh” against the “spirit.” Concupiscence stems from the disobedience of the first sin. It unsettles man’s moral faculties and, without being in itself an offense, inclines man to commit sins.
1264 Yet certain temporal consequences of sin remain in the baptized, such as suffering, illness, death, and such frailties inherent in life as weaknesses of character, and so on, as well as an inclination to sin that Tradition calls concupiscence, or metaphorically, “the tinder for sin” (fomes peccati); since concupiscence “is left for us to wrestle with, it cannot harm those who do not consent but manfully resist it by the grace of Jesus Christ.” Indeed, “an athlete is not crowned unless he competes according to the rules.”
2520 Baptism confers on its recipient the grace of purification from all sins. But the baptized must continue to struggle against concupiscence of the flesh and disordered desires. With God’s grace he will prevail
- by the virtue and gift of chastity, for chastity lets us love with upright and undivided heart;
- by purity of intention which consists in seeking the true end of man: with simplicity of vision, the baptized person seeks to find and to fulfill God’s will in everything;
- by purity of vision, external and internal; by discipline of feelings and imagination; by refusing all complicity in impure thoughts that incline us to turn aside from the path of God’s commandments: “Appearance arouses yearning in fools”;
- by prayer:
I thought that continence arose from one’s own powers, which I did not recognize in myself. I was foolish enough not to know . . . that no one can be continent unless you grant it. For you would surely have granted it if my inner groaning had reached your ears and I with firm faith had cast my cares on you.
1426 Conversion to Christ, the new birth of Baptism, the gift of the Holy Spirit and the Body and Blood of Christ received as food have made us “holy and without blemish,” just as the Church herself, the Bride of Christ, is “holy and without blemish.” Nevertheless the new life received in Christian initiation has not abolished the frailty and weakness of human nature, nor the inclination to sin that tradition calls concupiscence, which remains in the baptized such that with the help of the grace of Christ they may prove themselves in the struggle of Christian life. This is the struggle of conversion directed toward holiness and eternal life to which the Lord never ceases to call us.
One can also use the term Concupiscence in a different sense …in the “sinful way” …which may be what is throwing you off…
CCC
2514 St. John distinguishes three kinds of covetousness or concupiscence: lust of the flesh, lust of the eyes, and pride of life. In the Catholic catechetical tradition, the ninth commandment forbids carnal concupiscence; the tenth forbids coveting another’s goods.
Now what is Lust?
Lust:
2351 Lust is disordered desire for or inordinate enjoyment of sexual pleasure. Sexual pleasure is morally disordered when sought for itself, isolated from its procreative and unitive purposes.
also:
catholicreference.net/index.cfm?id=32697
catholicreference.net/index.cfm?id=34672
