The words foul play are often used as a synonym for "crime":

Sportsmanship is, in a basic sense, conforming to the rules of sport. This is a term called etiquicy. More grandly it may be considered the ethos of sport. It is interesting that the motivation for sport is often an elusive element. Sportsmanship...

Violence in sports

Foul (pronounced differently, /fʊːl/) is a Middle-Eastern food made from fava beans

Foul Play, a 1978 movie

Foul (football), in football (soccer), an unfair act by a player as deemed by the referee

Professional foul, in sports, a deliberate act of foul play, usually to prevent an opponent scoring

Foul ball, in baseball, a batted ball that lands in foul territory

Personal foul, in basketball, illegal personal contact with an opponent

Technical foul, in basketball, unsportsmanlike non-contact behavior; more serious infraction than a personal foul

Flagrant foul, in basketball, unsportsmanlike contact behavior; most serious foul and often results in ejection