1.)A scrub is a guy that thinks he's fly and is also known as a busta, always talkin bout what he wants, and just sits on his broke ass
2.) A scrub is a guy that can't get no love from me

Verb: rub (someone or something) hard so as to clean them, typically with a brush and water.

Noun: that one kid in your lobby that can't play for shit

Scrub meaning lower then someone, unworthy or worse , used as an insult

A scrub is a guy who thinks he’s fly,

Is also known as a busta

Some one that could be good at something but they don't work hard. Mostly referring to sports.

A scrub is a guy that thinks he's fly
And is also known as a busta (busta)
Always talkin' about what he wants
And just sits on his broke ass

Noun: Someone unwilling to admit their failures are any fault of their own, most typically in reference to, and originating from, competitive video games. Often implies the subject considers themselves somehow superior to their winning opponent, and believes that the game (or relevant, non-gaming task) should be adjusted so as to benefit those they believe are deserving (i.e. the subject).