What is a Blocking Foul in Basketball? (Full Explanation)

A blocking foul is when a player is not in legal guarding position and makes illegal contact with another player that impedes their progress, whether they have the basketball or not. A blocking foul is almost always called on a defensive player, as they are typically the ones creating contact and preventing another player from moving. It is possible for an offensive player to be called for a blocking foul, but it's much less common.