Nudity is placed on display. To be naked is to be without disguise. To be on display is to have the surface of one's own skin, the hairs of one's body, turned into a disguise which, in that situation, can never be discarded. The nude is condemned to never being naked. Nudity is a form of dress.
Nakedness is about disclosure and lived sexuality.
It's about being comfortable with our inner world at our most basic level, literally and figuratively stripped bare of all our cultural baggage. According to Berger, there are a few exceptional nudes in the European tradition of oil painting. Among the hundreds of thousands of nudes that make up the tradition there are perhaps a hundred of these exceptions. A couple examples would be Danae by Rembrandt and Helenne Fourment in a Fur Coat by Rubens.