https://www.merriam-webster.com/dictionary/onanism https://en.wikipedia.org/wiki/Onan Clearly what Onan did as quoted in the Bible was not masturbation strictly speaking. He refused to complete coitus with his mate, but determined to "spill seed". He was supposed to do something which was logical, refused for selfish motives and died. Strangely this term "onanism" attached to those who masturbate, which does not make sense. Biblically considered, "uncleanness" would be more applicable with men or women. But Biblically considered even normal and "sanctioned" coital sex makes both male and female "unclean" with a lot of fluids part of the activity.