Onanism

Onanism is a term that in the past was sometimes used to refer to masturbation. The term comes from the story of Onan in the Bible (Genesis 38:7-9), who was commanded by God to impregnate his late brother's wife (this was the practice of [levirate marriage]?). According to the Bible, whenever he had sexual intercourse with his brother's wife he spilt his semen upon the ground (probably a reference to coitus interruptus); the Bible says that he did this because (under the custom of [levirate marriage]?) the child would not be his, but his brothers. In response to this transgression, God killed Onan.

Since ancient times both Jewish and Christian authors have interpreted this passage as a condemnation of masturbation; but most modern biblical scholars agree that the story in fact has nothing to do with masturbation; Onan's sin was to violate the rules of levirate marriage, an ancient custom no longer practiced by Jews or Christians.