Onan

She conceived again and had a son, and she called him Onan.

Y'hudah said to Onan, "Go and sleep with your brother's wife - perform the duty of a husband's brother to her, and preserve your brother's line of descent."

However, Onan knew that the child would not count as his; so whenever he had intercourse with his brother's wife, he spilled the semen on the ground, so as not to give his brother offspring.

The sons of Y'hudah: 'Er, Onan, Shelah, Peretz and Zerach; but 'Er and Onan died in the land of Kena'an. The sons of Peretz were Hetzron and Hamul.

The sons of Y'hudah: First 'Er and Onan, but 'Er and Onan died in the land of Kena'an.

The sons of Y'hudah: 'Er, Onan and Shelah; the mother of these three was Bat-Shua the Kena'anit. 'Er, Y'hudah's firstborn, was wicked from ADONAI's perspective, so he killed him.