The term fornication refers to a sexual intercourse, which takes place between a man and a woman who are not married to each other. Along with adultery, fornication is still considered a misdemeanor in many states. However, the act is hardly prosecuted.
Some states have also removed such laws from their books on the basis that interventions such as this might be considered a violation to the right of privacy which is guaranteed by the Constitution itself. In states where it is a misdemeanor, it is punishable under Class 4 misdemeanor.