rumple v.

c. 1300, raumpen, "to climb; to stand on the hind legs" (of animals), from Old French ramper "to climb, scale, mount" (12c., in Modern French "to creep, crawl"), a word of uncertain origin, perhaps from Frankish *rampon "to contract oneself" (compare Old High German rimpfan "to wrinkle," Old English hrimpan "to fold, wrinkle"), via notion of the bodily contraction involved in climbing [Klein], from Proto-Germanic *hrimp- "to contract oneself."

Hence, of a person or a devil," "attack, behave menacingly, as a lion or wolf would" (late 14c.). Related: Ramped; ramping.

early 15c., riplen, "to crease, wrinkle;" 1660s, "to present a ruffled surface," of obscure origin, perhaps a frequentative of rip (v.), and compare rip (n.2) and rumple. Transitive sense, in reference to the surface of water, "cause to ripple, agitate lightly," is from 1786. Related: Rippled; rippling.