13 Let us walk properly, as in the day, not in revelry and drunkenness, not in lewdness and lust, not in strife and envy.
and lust [sexual excess],
The Greek word for “lust” means debauchery. It portrays the idea of someone who has lost all sense of shame. This person operates on unbridled lust with a sense of insolence and shamelessness.
Most people conceal their shame, but not this person. He does not sin in secret and does not care who sees him. He will make a public exhibition of himself and does not care what people think of him. He is so deeply in the grip of unadulterated lust that he flaunts his sin publically; it is a wanton attitude.
The person who reaches the level of debauchery is at the mercy of his lust and emotions. He cannot control himself. Neither does he respect the rights of others. He is audacious and abusive with his sin. Sexual sin is the sin itself, but “lust” is a lifestyle of sexual excess.
As a note of perspective, the Bible presents sexual intercourse within marriage as something beautiful:
He 13: 4 Marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge.
It is possible that some Christians can commit sexual sins to the level of debauchery.
The Christian who has lost shame for his sin is in a state of complete reversionism from God. His will and openness to God are totally shut down. He does not care how others view him but is completely indifferent to public opinion regarding public decency. Since he has no self-respect, he does not care about what the church thinks or how Christians view him.
The person with this sin has lost all sense of self-control with no sense of self-restraint. We find the same Greek word in Ephesians.
Eph 4: 19 who, being past feeling, have given themselves over to lewdness, to work all uncleanness with greediness.
When a person abandons the Word of God in his life, then he is on the road toward reversionism. If he stays on that road long enough, he can reach the state of giving himself “over to lewdness” or a complete lack of shame for his sin.
For a further study of sex in the Bible see my study online: http://versebyversecommentary.com/articles/theology-of-sex/