It means that you’re the son of a whore, a
woman that has slept around a lot.
It can also be used towards a
father with context, which would mean you’re the son of a man who is weak, or a pussy at heart. Another insult for this is ‘bitch made’ meaning you’re raised by a
bitch.
‘You’re moms a hoe, so that makes you a son of
bitch’
‘You bitch made, your dads a
weak little pussy and you’re just like him you son of a
bitch.‘