scrub

A person who (usually male) isn't responsible for themselves, has accomplished nothing in life, is lazy, entitled and selfish, but thinks they're just absolutely fucking genius. A scrub will feed off of you emotionally and financially, convincing you first that they've just cut a bad deal in life but are getting back on their feet and at first you can't believe somebody so nice and smart is always being treated so mean. Then over the course of months or years, it dawns on you you're being played for a sucker.

"Jen's new boyfriend is a total scrub. He fucked his car up and just uses hers to go out to the bar while she walks to work every day."