Someone who weighs 120 pounds. A little fiend rat, also known as a "chad" who thinks he is tough, but in reality, only weighs 120 pounds and can't fight his way out of a wet paper bag.
Giant Killer: Man, nigga steve wants to bust me up this weekend, what you think I should do??
Yob: Man, that chad is a buck 20, you can bust that fool up!! And if needed, I'ma just drop him with a flying roundhouse!!