Dead beat dad

[Sonia]

a loser father who is almost never around, flaky, and breaks promises, usually made to his kids.

[Sarah]

A man who does not pay child support and/or maintain regular contact with his children. Or a bum who, though still sleeping with the mother, does nothing to contribute to the household either financially or by taking care of the home/children. Often an abusive man or an addict. Always lazy and self absorbed.