What is the meaning of Overdraw?

To withdraw more money from an account than there is credit; to make an overdraft

To use a device for shooting arrows shorter than the draw of the bow.

To exaggerate.

To draw over the top of existing content.

To draw the air in through a harmonica while adjusting the mouth so that the note goes up a half tone.

The process by which, during the rendering of a three-dimensional scene, a pixel is replaced by one that is closer to the viewpoint, as determined by their Z coordinates.

Source: wiktionary.org