In sports, a foul is an inappropriate or unfair act by a player as deemed by a referee. A foul may be intentional or accidental, and often results in a penalty.
Individual sports may have different types of fouls. For example, in basketball, a personal foul involves illegal personal contact with an opponent. A technical foul refers to unsportsmanlike non-contact behavior, a more serious infraction than a personal foul. A flagrant foul involves unsportsmanlike contact behavior, considered the most serious foul and often resulting in ejection from the game.
In association football, a foul is an unfair act by a player as deemed by the referee. In association football or rugby, a professional foul is a deliberate act of foul play, usually to prevent an opponent scoring.
Kinjite are various fouls that a sumo wrestler might commit that will cause him to lose the bout.
Facial is a term used in some contact sports to refer to a foul that involves one player hitting another in the face.