A bully is a blustering, quarrelsome and overbearing sort. They never grew out of it; they acted that way in elementary school, and it carried through to present day. They are often physically dominant, which makes up for their insecurities and deficiencies in other areas. (Like, say, brain power.) Every office has one. The trick is to know their buttons so you can discreetly and strategically push them to the delight of your co-workers.