ONAN. - Second-born son of JUDAH, son of the patriarch JACOB, born to him by his Canaanite wife, SUE.
After his brother HER died without issue, at his father’s advice and in accordance with the custom of the levirate (v.), which was practiced even before Mosaic legislation, Onan married his brother’s widow, THAMAR. But unwilling that any offspring born of the union should be reckoned to his deceased brother, as the levirate required, he joined himself to his wife in such a way as to prevent conception. For this shameful crime he was punished by the Lord with death (Gen. 38:2-4; 46:12). The sin against nature by which procreation is deliberately prevented is named after him and is called “onanism.”