Old English crypel, "one who creeps, halts, or limps, one partly or wholly deprived of the use of one or more limbs," related to cryppan "to crook, bend," from Proto-Germanic *krupilaz (source also of Old Frisian kreppel, Middle Dutch cropel, German krüppel, Old Norse kryppill). Possibly also related to Old English creopan "to creep" (creopere, literally "creeper," was another Old English word for "crippled person").
In place-names in Middle English, cripple meant "a low opening, a burrow, a den" (such as one must bend or creep to enter), a sense perhaps preserved in the U.S. use of cripple for "a dense thicket or swampy low-land" (1670s).
mid-13c., "to move slowly, be crippled," from cripple (n.). Transitive meaning "make a cripple of, lame, partially disable by injury to a limb or limbs" is from early 14c. (implied in crippled). Related: Crippling.