flail (n.) Look up flail at Dictionary.com
"implement for threshing grain," c.1100, from an unrecorded O.E. *flegel, which probably represents W.Gmc. *flagil (cf. M.Du., Low Ger. vlegel, O.H.G. flegel, Ger. flegel), a borrowing of L.L. flagellum "winnowing tool, flail," from L. flagellum "whip." The verb is 15c., from the noun; originally "to scourge;" sense of "to move like a flail" is from 1874. Related: Flailed; flailing.