Within criminal statutes, the term ‘lewd and lascivious cohabitation’ means the living together of a man and woman not married to each other as husband and wife. "Lewd and lascivious cohabitation" means a living together in a state of fornication or adultery. [State v. Naylor, 68 Ore. 139 (Or. 1913)].
The following is an example of a state statute (Virginia) referring to the term:
Va. Code Ann. § 18.2-345. Lewd and lascivious cohabitation.
If any persons, not married to each other, lewdly and lasciviously associate and cohabit together, or, whether married or not, be guilty of open and gross lewdness and lasciviousness, each of them shall be guilty of a Class 3 misdemeanor; and upon a repetition of the offense, and conviction thereof, each of them shall be guilty of a Class 1 misdemeanor.