If someone is swinging the lead, they are pretending to be ill to avoid working. Note: Lead is a very heavy metal. It is a question of getting the right benefits to the right people, and we want to stop anyone swinging the lead. Note: In the past, when a ship was in shallow water, one of the sailors would drop a piece of lead on a string, called a plumbline, over the side of the ship to find out how deep the water was. Sometimes sailors would just swing the plumbline, because they were too lazy to do the work properly. `Plumb the depths' is also based on this practice.