Licentious, libertine, lewd, wanton, lustful, lascivious, libidinous, lecherous all suggest unchaste habits, especially in being given to or indicative of immorality in sex relations.
Licentious basically implies disregard of the restraints imposed by law or custom for the enforcement of chastity; the term stresses looseness of life and of habits rather than the imperiousness of one's desires.
Libertine suggests a more open and a more habitual disregard of moral laws, especially those pertaining to the sex relations of men and women.
Lewd often carries strong connotations of grossness, vileness, and vulgarity which color its other implications of sensuality, dissoluteness, and unconcern for chastity. As a result it is applied less often than the preceding terms to persons, or to the manners, thoughts, and acts of persons, who retain in their immorality evidence of breeding, refinement, or gentility.
Wanton (see also SUPEREROGATORY ) implies moral irresponsibility or a disposition or way of life marked by indifference to moral restraints; it often suggests freedom from restraint comparable to that of animals, thereby connoting lightness, incapacity for faithfulness or seriousness, or a generally unmoral attitude.
Lustful implies the influence or the frequent incitement of desires, especially of strong and often unlawful sexual desires.
Lascivious, like lewd, definitely suggests sensuality, but it carries a clearer implication of an inclination to lustfulness or of a capacity for inciting lust. Libidinous and lecherous are the strongest of all these terms in their implications of deeply ingrained lustfulness and of debauchery.
Libidinous distinctively suggests a complete surrender to one's sexual desires.
Lecherous clearly implies habitual indulgence of one's lust, the term often being used when any of the others would seem too weak to express one's contempt.