Also known as a 'busta', A 'scrub' is Atlantan slang for a lazy, greedy, hardly-working and selfish male who doesn't have a job, is usually broke, lives with their parents and often treats their girlfriend/boyfriend poorly while thinking themselves highly compared to what they really are. The female counterpart of a 'scrub' is known as a 'pigeon'.
"A scrub is a guy that thinks he's fly
And is also known as a buster Always talking 'bout what he wants
And just sits on his broke ass"
Someone who complains in a multiplayer game that his opponent plays "unfair", "cheap" or "without honor". He makes up rules and will always find external reasons why he loses, therefore being unable to truly improve.
"USING THAT WEAPON IS SO CHEAP, FUCKIN NOOB" - "All I do is playing the game, scrub."