1530s in the literal sense of "to strip (a sheep) of fleece," from fleece, n.. From 1570s in the figurative meaning "to cheat, swindle, strip of money." Related: Fleeced; fleecer; fleecing.

"wool coat of a sheep," Old English fleos, flies "fleece, wool, fur, sealskin," from West Germanic *flusaz (cognates: Middle Dutch vluus, Dutch vlies, Middle High German vlius, German Vlies), which is of uncertain origin; probably from PIE *pleus- "to pluck," also "a feather, fleece" (cognates: Latin pluma "feather, down," Lithuanian plunksna "feather").