And she again conceived and bore a son, and she called his name Onan.

Then Judah said to Onan, Go in to thy brother's wife, and fulfil to her the brother-in-law's duty, and raise up seed to thy brother.

But when Onan knew that the seed should not be his own, it came to pass when he went in to his brother's wife, that he spilled it on the ground, in order to give no seed to his brother.

The LORD considered what Onan was doing to be evil, so he put him to death, too.

The sons of Judah: Er, Onan, Shelah, Perez, and Zerah (but Er and Onan died in the land of Canaan). And the sons of Perez were Hezron and Hamul.

The sons of Judah: Er and Onan. And Er and Onan died in the land of Canaan.

The sons of Judah: Er, Onan and Shelah; [these] three were born to him from Bathshua the Canaanite. Now Er, Judah's firstborn, [was] evil in the sight of Yahweh, and he put him to death.