Lewd behavior, also called lewd and lascivious conduct, is considered a crime by the federal government and all fifty states, though the definition and. lewd and lascivious. adj., adv. references to conduct which includes people living together who are known not to be married, entertainment which aims at. Define lewd. lewd synonyms, lewd pronunciation, lewd translation, English dictionary dirty - (of behavior or especially language) characterized by obscenity or. The definition of lewd is offensive sexual behavior. An example of lewd is an old man at a county fair leering at young girls. YourDictionary definition and usage. Criminal Law Lawyer Source describes lewd conduct as "any unlawful act Typical examples of lewd conduct charges are sex acts in public places or in view of. Lewd has to do with sexual behavior or remarks that are highly inappropriate or obscene, often because of what's done or said is in public or to someone who.