Except in the case allowed by God, Deuteronomy 25:5. An unclean thing; an abominable thing, like the uncleanness of a menstruous woman, which is oft expressed by this word: Heb. a separation or removing, i.e. a thing deserving separation or exclusion from society with others; or a thing to be removed out of sight or out of the world.
Related Commentaries of Leviticus 20:21
Leviticus 20:21
21 And if a man shall take his brother's wife, it is an unclean thing: he hath uncovered his brother's nakedness; they shall be childless.