Poaching

From Ultipedia

When a defender moves away from their marker to try and make an interception on a pass to another player. This is commonly done when trapping the line. The marker tries to oblige the handler to throw alongside the sideline. The poacher is positioned close to the line, as to prevent a huck. This requires the marker not to allow break passes. This defense is not suitable when a handler is good enough to make outside throws down the field. Note that this sort of position-defense leaves a cutter undefended.