See her nakedness In this and several of the following verses, uncovering nakedness plainly appears to mean not marriage, but fornication or adultery.
Related Commentaries of Leviticus 20:17
Leviticus 20:17
17 And if a man shall take his sister, his father's daughter, or his mother's daughter, and see her nakedness, and she see his nakedness; it is a wicked thing; and they shall be cut off in the sight of their people: he hath uncovered his sister's nakedness; he shall bear his iniquity.