A term used in the friendliest manner and used for greeting by all races except Elmer Fudds, then pronounced kwacker and exclaimed with malice. Possible origin of word from early 19th century(1810 to 1840) coined when the sound of the whip was the slave's (usually black) or the endentured servant's (usually white,latino,or asian)or the employee's/associate's (with a healthy salary/401k/IRA/HMO/pph's etc.) call to
pick up the pace at any given jobsite. Whether it be cotton fields,railroad tracks,bridges,tunnels, or any other private or municipal project that required a large work force therefore an inherent high number of slackers(pre-union era)made it necessary to get the attention of said unmotivated workers,By making the end of a bullwhip travel faster than
the speed of sound("cracking noise")
The technique, when practiced regularly can cause an adequate statement of authority. The man/or woman dealing out this authority was called "the cracker".