Short for Parkinson's Disease. A word commonly used to describe someone portraying the traits of Parkinson's Disease. such traits include random shaking, excessive sweating, slouched posture, dragging feet, slurred speech. If these symptoms continue for a long duration of time have your acquaintance see a doctor.
Person A: Dude, why are you shaking
Park's person: Iunno man I'm trying to stop
Person A: Dude you have Park's