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.