Technically speaking, naked implies that a person is unprotected or vulnerable. It also describes something that is unadorned or without embellishment, as in the oft-mentioned naked truth. Nude, on the other hand, means one thing: unclothed.

Think of it this way: if you doff your duds to pose while descending a staircase for a tasteful painting done by a respected artist, then you're nude. If a bunch of paparazzi suddenly burst in through the studio door and take your picture without permission, you are suddenly naked.

And as the late great humorist Lewis Grizzard once pointed out, "Naked is when you ain't got no clothes on. Nekkid is when you ain't got no clothes on and you're up to something."

http://mentalfloss.com/article/12571/whats-difference-between-naked-and-nude