Prostitution is the act of performing sexual activity in exchange for money. The legal status of prostitution varies greatly between different jurisdictions, from being punishable by death to being completely legal.

The term is also used loosely by some to refer to sexual activities of which they disapprove, such as sexual promiscuity or sex outside marriage. Cultural usage varies widely, and the use of the term as a pejorative indicates acts that are not formally considered prostitution in a cultural context.

Pornographic actors and actresses get paid for having sex, but are not generally referred to as prostitutes. If a woman has sexual intercourse with a man who supports her financially but doesn't live with her, then she is called a mistress, and is again not normally considered a prostitute. If a man has sexual intercourse with a woman who supports him financially but doesn't live with him, then he is called a kept man, and is again not normally considered a prostitute.