Definition
Also called a "hosel rocket", this is when you hit the ball with the hosel (club's neck) instead of the clubface, resulting in an erratic shot. If you are a right-handed golfer, this results in the ball traveling severely right of your target and usually out of play. This is one of the worst types of shots in golf because it almost always results in a penalty stroke.
Usage
I have a bad case of the shanks right now and I can't get rid of them!