Offensive pass interference is a penalty in football that is called on an offensive player when the player performs an illegal action against a defensive player to prevent a pass from being defended properly. For example, if a pass is in the air and the defensive player is defending the offensive player from catching the ball, the offensive player shoving the defensive player to the ground would be offensive pass interference. Offensive pass interference is a 10 yard loss against the offense.
For defensive pass interference, the same rules apply. If a defender were to prevent an offensive player from catching the ball by illegal means, such as shoving, a defensive pass interference would be called.