Genesis 38:4
Ver. 4. And she conceived again, and bare a son,.... As soon as she well could:
and she called his name Onan; the first son Judah gave the name to, but his wife named this, so called from grief or sorrow; the reason of it, according to the above Targum, was,
"because his father would mourn for him;''
he was a Benoni, see Ge 35:18, whose sin and immature death caused sorrow.