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).
- Ejaculating outside the vagina during intercourse; (the performing of) coitus interruptus.
- 1839, Hypochondriasis, hysteria, chorea, epilepsy, apoplexy, and palsy, constitute part of the list of dire maladies induced or immediately excited, by onanism and immoderate or ill-timed coition. The memory and intellectual faculties, in general, are enfeebled, and there are instances of complete idiocy, brought on by early and continued onanism, and of insanity from similar excesses later in life. -- The Eclectic Journal of Medicine. Vol 3, No 4. Nov 1894. Haswell, Barrington, and Haswell: Philadelphia. p145
- See also Thesaurus:masturbation