Top Definition
A pedant writes:

This is a mis-spelling of the more correct onanism.

Onan is a person described in the Bible (book of Genesis). He was the second son of Judah. His name is the origin for the sexual term onanism (synonym of masturbation), which many consider to be based on a misinterpretation as it more properly refers to spilling seed...

After his older brother Er died Onan was to marry Er's widow Tamar. According to the Bible, when he had sexual intercourse with his brother's wife he spilt his seed upon the ground (Genesis 38:7-9); the Bible says that he did this because (under the custom of levirate marriage) the child would not be considered his, but his late brother's. In response to this transgression, God killed Onan.
'Onerism, you ill educated peasant, surely you mean Onanism!'

Instead of 'Oh Fuck' one would use the following 'By Onan's withered Balls!'

Well, you could if you wanted ;-)
by Nickdubya January 12, 2006
Wanking. Masturbation.
Tossers! Shouldn't they be practising onerism in the privacy of their own rooms?
by brittner September 18, 2003
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