Criminal Conversation Definition

noun
An act of adultery that gives rise to a cause of action on the part of the injured spouse.
American Heritage
Webster's New World

In tort law, having sexual relations with another person’s spouse, especially the act of a man having sexual intercourse with another man’s wife. This tort has been abolished in most states. See also alienation of affections, adultery, fornication, and rape.

Webster's New World Law

(law) Unlawful sexual intercourse with a married person; adultery.

Wiktionary
Synonyms: