A violation that occurs when a player makes illegal personal contact with an opponent. What is considered "illegal personal contact" is decided by the referees, but in general, a player cannot push, hold, charge into, or impede the progress of an opposing player without established position or by extending an arm, leg or hip. Any conduct that is deemed unsportsmanlike is also considered a foul ("technical foul"). Any contact that is deemed excessive, intentional and/or unnecessary is classified as a "flagrant foul".
When a player commits a personal foul (any foul that is not a technical foul or a flagrant foul) while the person is not in the act of shooting, the opposing team gains possession of the ball to inbound it from the out-of-bounds area that is closest to the spot of the foul. When a player commits a personal foul while the person is in the act of shooting, the opposing player who draws the foul is awarded two free throws if his two-point field goal attempt misses and three free throws if his three-point field goal attempt misses. If the field goal attempt is made when the opposing player draws a foul, he is awarded the points and one free throw.
In the NBA, or any league that uses 48-minute games, a player is ejected from the game (or "fouls out") when he commits six personal fouls. In NCAA, or any league that uses a shorter game clock, a player fouls out when he commits five personal fouls.
Also in the NBA, a player who draws a foul is awarded two free throws when the opposing team is in a penalty situation for committing too many defensive or loose-ball fouls in a quarter.