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general::
Also, break or bust one's ass or balls or butt or chops. 1. Exert one-self to the utmost, try extremely hard, as in I've been breaking my ass to finish early. This expression is considered vulgar slang; both ass, for backside or buttocks, and balls, for male genitals, are rude; butt, for buttocks, and chops, for either the mouth or the legs, are informal and emphatic but not quite as offensive. For a more polite synonym, see BREAK ONE'S BACK. [Slang; first half of 1900s] 2. break someone's ass. Also, bust someone's chops. Thrash or harass someone, as in Jim threatened to break Tim's ass, or The boss broke his workers' chops to improve service. [Vulgar slang; mid-1900s]
American Heritage Idioms