"to strike repeatedly" (with something), c. 1500, a word of unknown origin; according to one old theory it is perhaps from early 13c. pelten "to strike," a variant of pilten "to thrust, strike," from an unrecorded Old English *pyltan, from Medieval Latin *pultiare, from Latin pultare "to beat, knock, strike," or [Watkins] pellere "to push, drive, strike" (from PIE root *pel- (5) "to thrust, strike, drive"). OED doubts this. Or it might be from Old French peloter "to strike with a ball," from pelote "ball" (see pellet (n.)) [Klein].
From 1680s as "to go on throwing (missiles) with intent to strike." The meaning "proceed rapidly and without intermission" (1831) is from the notion of beating the ground with rapid steps. Related: Pelted; pelting.
early 15c., "the skin of a fur-bearing animal with the hair on it," especially of the smaller animals used in furriery, a word of uncertain origin, perhaps a contraction of pelet (c. 1300 in Anglo-Latin), from Old French pelete "fine skin, membrane," diminutive of pel "skin," from Latin pellis "skin, hide" (from PIE root *pel- (3) "skin, hide"). Or perhaps the English word is a back-formation Anglo-French pelterie, Old French peletrie "fur skins," from Old French peletier "furrier," from pel. It was later used also of skins stripped of wool or fur (1560s).