Foul play is a term used to describe criminal or violent activity that causes somebodys death. It is often used when the police suspect that a death was caused by murder or other criminal activity. Foul play can also refer to any action that is dishonest, unfair, or illegal, especially one that happens during a sports game. Examples of foul play include cheating, bribery, and match-fixing. In general, foul play refers to any activity that is against the rules or laws and is intended to gain an unfair advantage or cause harm to others.