A foul in association football is an unfair act by a player which is deemed by the referee to contravene Law 12 of the Laws of the Game.

For an act to be a foul it must:

• be a specific offence listed in Law 12 of the Laws of the Game (other infractions, for example technical infractions at restarts, are not deemed to be fouls);
• be committed by a player (not a substitute);
• be committed against an opponent, when applicable (a player striking the referee or a teammate, for example, is not a foul, but a misconduct
  Misconduct (football)
  Misconduct in association football is any conduct by a player that is deemed by the referee to warrant a disciplinary sanction in accordance with Law 12 of the Laws of the Game. Misconduct may occur at any time, including when the ball is out of play, during half-time and before and after the...
  
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• occur while the ball is in play.

As can be seen from the above not all infractions of the Laws are fouls, rather they may constitute — and be punished as — technical infractions and/or misconduct

Misconduct (football)

Misconduct in association football is any conduct by a player that is deemed by the referee to warrant a disciplinary sanction in accordance with Law 12 of the Laws of the Game. Misconduct may occur at any time, including when the ball is out of play, during half-time and before and after the...

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Direct free kick offences

A direct free kick

Direct free kick

A direct free kick is a method of restarting play in a game of association football following a foul. Unlike an indirect free kick, a goal may be scored directly against the opposing side without the ball having first touched another player.-Award:...

 offence occurs when a player commits any of the following in a manner considered by the referee to be careless, reckless or using excessive force:

• Kicking or attempting to kick an opponent
• Tripping or attempting to trip an opponent
• Jumping at an opponent
• Charging an opponent
• Striking or attempting to strike an opponent
• Pushing an opponent
• Tackling an opponent

Or commits (one of) the following offences:

• Holding an opponent
• Spitting at an opponent
• Handling the ball deliberately (except for the goalkeeper within his own penalty area).

In determining whether a player deliberately (direct free kick), or accidentally (no offence) handled the ball, the referee has several different considerations- whether the arm moved towards the ball, how long the player had to react, whether the player had his eyes on the ball and whether the players arm is in a "natural" or an "unnatural" position.

If a direct free kick offence occurs within a team's own penalty area it becomes punishable by a penalty kick, irrespective of the position of the ball, provided the ball was in play.

Indirect free kick offences

Fouls punishable by an indirect free kick

Indirect free kick

An indirect free kick is a method of restarting play in a game of association football. Unlike a direct free kick, a goal may not be scored directly from the kick. The law was derived from the Sheffield Rules that stated that no goal could be scored from a free kick...

 are:

• When a goalkeeper, inside his own penalty area:
  • takes more than six seconds while controlling the ball with his hands before releasing it from his possession
  • touches the ball again with his hands after it has been released from his possession and has not touched any other player
  • touches the ball with his hands after it has been deliberately kicked to him by a team-mate
  • touches the ball with his hands after he has received it directly from a throw-in by a team-mate

• When any player in the opinion of the referee:
  • plays in a dangerous manner
  • impedes the progress of an opponent
  • prevents the goalkeeper from releasing the ball from his hands
  • commits any other offence, not previously mentioned in Law 12, for which play is stopped to caution or dismiss a player

Advantage

According to the principle of advantage, play should be allowed to continue when the team against which an offence has been committed will benefit from ongoing play. The referee indicates this by calling "advantage" and extending both arms in front of his body.

This means that a foul will not be called if letting play continue is more advantageous to the fouled team than stopping play for a free kick. However, if the anticipated advantage does not ensue at that time, the referee may then stop play and penalize the original offence.

Other offences

Not all infractions of the Laws are fouls. Non-foul infractions may be dealt with as technical infractions (e.g. as breaching the rules governing the restarts of play) or misconduct (these are punishable by a caution or sending-off). Note that severe or persistent fouls may constitute misconduct.

See also

• Laws of the Game
• Misconduct (football)
  Misconduct (football)
  Misconduct in association football is any conduct by a player that is deemed by the referee to warrant a disciplinary sanction in accordance with Law 12 of the Laws of the Game. Misconduct may occur at any time, including when the ball is out of play, during half-time and before and after the...
  
  
• Tactical foul
  Tactical foul
  The term "tactical foul" is used in football to describe fouls which attempt to upset the opposing team's flow of football. Such fouls may be used in the Catenaccio system in football...