Forbidden relationships in Judaism

Forbidden relationships in Judaism (איסורי ביאה Isurey bi'ah) are intimate relationships which are forbidden by prohibitions in the Torah or rabbinical injunctions. Some of these prohibitions—those listed in Leviticus 18, known as arayot (Hebrew: עריות)—are considered such a serious transgression of Jewish law that one must give up one's life, rather than transgress one of them.