Read the dictionary definition of gad. All definitions for this word.
1. a sharp prod fixed to a rider's heel and used to urge a horse onward
1. cowboys know not to squat with their spurs on
2. an anxiety disorder characterized by chronic free-floating anxiety and such symptoms as tension or sweating or trembling or lightheadedness or irritability etc that has lasted for more than six months
3. wander aimlessly in search of pleasure
See also: Merriam-Webster definition of gad