In basketball, face guarding is a defensive technique used to prevent the offensive player from getting open for a shot. The defender places their hand or body in front of the player's face, so they can't see the basket. This makes it difficult for the offensive player to shoot or make a pass.
Face guarding is legal as long as the defender doesn't put their hand in the player's face or obstruct their view with their body. If they do, it's a foul.
Face guarding can be frustrating for offensive players because it's hard to get open for a shot when you can't see the basket. But it's an effective way to defend against shooters and playmakers.