skinny-dip
To swim in the nude, especially in a public place or someone else's private property. We used to skinny-dip in one of our neighbors' pools—until they called the police on us one night. Our dorms were really close to a beach, so people skinny-dipped down there all the time.
skinny-dipping
The practice or act of swimming in the nude, especially in a public place or someone else's private property. After a few drinks around the bonfire on the beach, we all decided to strip down and go skinny-dipping. I don't really like skinny-dipping, to be honest. It is always more embarrassing than thrilling.