polecat (n.)

"small, dark-brown, northern European predatory quadruped of the weasel family," noted as a chicken-thief and for its strong, offensive smell, early 14c., pol-cat, from cat (n.); the first element is perhaps Anglo-French pol, from Old French poule "fowl, hen" (see pullet (n.)); so called because it preys on poultry [Skeat]. The other alternative is that the first element is from Old French pulent "stinking." Originally the European Putorius foetidus; the name was extended to related North American skunks by 1680s.