early 13c., hurlen, "to run against (each other), come into collision," later "throw forcibly" (c. 1300); "rush violently" (late 14c.); perhaps related to Low German hurreln "to throw, to dash," and East Frisian hurreln "to roar, to bluster." OED suggests all are from an imitative Germanic base *hurr expressing rapid motion; see also hurry (v.). For difference between hurl and hurtle (which apparently were confused since early Middle English) see hurtle (v.).
late 14c., "rushing water," from hurl (v.). Mid-15c. as "strife, quarrel;" sense of "act of throwing violently" is from 1520s.