Here the idiom "uncover the nakedness" of someone means "have sexual relations" with someone. See how you translated this idiom in [Leviticus 18:6](../18/06.md). Alternate translation: "to have sexual relations with her" (See: [[rc://en/ta/man/jit/figs-idiom]])
This is the time every month when a woman bleeds from her womb. The words "impurity" and "uncleanness" both occur to emphasize how disgusting a man is to consider her nakedness at that time. (See: [[rc://en/ta/man/jit/figs-doublet]])