father's wife. See Gen 35:22. 2 Samuel 16:20-23; 1 Kings 2:17, and 1 Corinthians 5:1-5. This verse clarifies Genesis 9:22-25, and see also Leviticus 20:11.
Related Commentaries of Leviticus 18:8
Leviticus 18:8
8 The nakedness of thy father's wife shalt thou not uncover: it is thy father's nakedness.