Today, this generally refers to masturbation, but originally, Onanism referred to any sexual activity that resulted in semen being spilled in a non-procreative manner, especially due to the withdrawal method of birth control, so called after the Biblical figure of Onan, who shot his load pretty much anywhere except inside a pussy.
In the book of Genesis, Onan was charged by the law of his clan to provide offspring to his dead brother’s widow, but because any children she bore would not legally be considered his heir, and because he thought this law was total bullshit, he always pulled out before he climaxed and shot his load on the ground. He still got to fuck the chick, you see, but this way he wouldn’t have to worry about having any little fuckers around to mess up his business. Over time, the broader meaning of Onanism, i.e. the spilling of a man’s seed on the ground, narrowed until it came to refer to masturbation in particular.
Eventually, God got all pissy about Onan flouting the law and refusing to get his sister-in-law knocked up, so one day God just flipped out like a ninja and fucking killed him. Everyone was like, Oh shit! Did you see what God just fucking did to Onan? That was fucked up, dude! But that was like, 5000 years ago or some shit, and we figure God must have totally mellowed out since then, and maybe had a few cold beers, because if jerking your seed outside of a cunt was still punishable by death, then we all would’ve gotten lightning raped by the Big Guy and all of our horny asses would have been grass a long time ago.
And really, we figure God just had it out for Onan from the get-go and was looking for an excuse to kill him, because the rest of Onan’s family did some pretty freaky shit too, some of it a lot worse than busting your nut on the floor of your tent, like the time Onan’s dad Judah fucked his daughter-in-law because he was drunk or something and thought she was a whore, and he tried to keep it all a secret, but it turns out he got her preggers with twins, and then she totally busted him Jerry Springer-style in front of everybody, and none of those people got waxed, just Onan, so maybe God is just a petty little bitch who talks a lot of shit and kills people for no good reason.
So anyway, yeah, “Onanism” means “jerking off.”
1. Since I was twelve or so, Onanism has been my true calling.
2. The Church calls Onanism a sin. I guess sinning helps me sleep at night.
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