"hind-quarters, buttocks of an animal," c.1440, from a Scand. source (cf. Dan., Norw. rumpe, Swed. rumpa), cognate with M.Du. romp, Ger. Rumpf "trunk, torso." Sense of "small remnant" derives from "tail" and is first recorded 1649 in ref. to the Eng. Rump Parliament (December 1648-April 1653).