In basketball, you “foul” someone by making illegal contact that the refs judge to give the other player an unfair advantage. Common examples are holding, pushing, blocking, hand-checking, tripping, charging into a defender, or hitting an opponent’s arm while they’re shooting.

Basic idea

  • On defense, you can stay in front of the player and contest the shot, but you cannot grab, shove, or hit them.
  • On offense, you can also get called for fouls if you push off, charge into a defender who has established position, or set an illegal screen.
  • If the contact is severe or dangerous, it can be called a flagrant or technical foul instead of a normal personal foul.

Simple examples

  • A defender reaches in and slaps the shooter’s wrist: foul.
  • A defender steps into position and the ball handler runs into them: often a charge on the offense.
  • A player uses an elbow or excessive contact: can be a more serious foul.

In plain English

If the contact is part of normal basketball movement, it may be legal. If it involves grabbing, pushing, impeding, or hitting in a way that changes the play, it usually becomes a foul.

TL;DR: You foul someone in basketball by making illegal contact that the referee calls against you, like pushing, holding, hitting, or charging.