en_tn/lev/18/11.md

Do not uncover the nakedness of

Here the idiom "uncover the nakedness" of someone means "have sexual relations" with someone. See how you translated this idiom in Leviticus 18:6. Alternate translation: "Do not have sexual relations with" (See: rc://en/ta/man/jit/figs-idiom)

your father's wife's daughter

Possible meanings are 1) "your half-sister" or 2) "your stepsister." Here the man does not have the same father or mother as the woman. They became brother and sister when their parents married.