This particular work of the flesh differs from adultery and fornication. An act of adultery can be a single, lustful glance upon someone other than your spouse. An act of fornication could be a few minutes looking at pornography. Uncleanness, on the other hand, is a perpetual state of being.
The term unclean comes from the Greek word "akatharsia" and is found 40 times in the New Testament. Akatharsia denotes a physical and moral impurity and is a strong word in the Greek language. It is a word tied to the stench and decay of a corpse.
"And lest, when I come again, my God will humble me among you, and that I shall bewail many which have sinned already, and have not repented of the uncleanness and fornication and lasciviousness which they have committed." - 2 Corinthians 12:21
"Who being past feeling have given themselves over unto lasciviousness, to work all uncleanness with greediness." - Ephesians 4:19
"But fornication, and all uncleanness, or covetousness, let it not be once named among you, as becometh saints." - Ephesians 5:3
"Mortify therefore your members which are upon the earth; fornication, uncleanness, inordinate affection, evil concupiscence, and covetousness, which is idolatry." - Colossians 3:5
Uncleanness is the result of a constant state of sinful living. A person can easily see the repercussions of a lifestyle filled with sexual escapades, excessive drinking, and a mouth that utters lies just to name a few. In the Hebrew, the word unclean is "tame" (pronounced tah-me) and it means to be "crushed, subdued, depressed, and spiritless".
God wants more for us than to be defeated and stuck in a lifestyle that perpetually destroys us. When a person accepts Jesus, they are no longer crushed or subdued, but given new life (Eph. 2:5) and become "more than conquerors through Him that loved us" (Rom. 8:37)!
Next work of the flesh: lasciviousness