An illegal forward handoff is a penalty in Football that is called on a team when a forward handoff occurs following a forward pass. An illegal forward handoff involves a player giving the ball to a teammate who is running ahead of them after a forward pass. This penalty results in a 5 yard loss for the offending team.
The reason this is illegal is because a forward handoff is considered a forward pass. Therefore, a forward handoff may occur behind the line of scrimmage before a regular forward pass and be considered legal.