onanism

Etymology

From Onan + -ism. In the Book of Genesis, Onan, son of Judah, in fulfillment of the laws of levirate marriage was to impregnate his brother Er's widow, Tamar, in order to raise offspring from the union in his brother's name. In order to avoid raising descendants for his late brother, however, Onan "spilled his semen on the ground when he went in to his brother's wife, so that he would not give offspring to his brother" (Genesis 38:9).