Other forms: flailing, flails, flailed
To flail is to wave the arms about wildly. Flail about, flailing arms, flail at the water.
It is uncontrolled by definition — flailing is what somebody does when they have lost the thread or the footing. The noun is a threshing tool: two sticks joined by a chain, swung to beat grain from straw, and the loose swinging is exactly where the verb comes from.
1verbflailTo wave the arms about wildly.
“The drowning man flailed his arms in the water, shouting for help.”
2nounthreshingA threshing tool of two sticks joined by a chain.
“An old wooden flail hung on the barn wall beside the scythe and the pitchfork.”
flail is a wild swinging.
Old English fligel names the threshing tool, from a Germanic word probably from Latin flagellum, a whip. Flagellate comes from the same whip.
Proto-West Germanic
*flagil
Old English
fligel
Middle English
flayle
English, today
flail
Built from
From Middle English flayle, from earlier fleil, fleyl, fleȝȝl, from Old English fligel, flegel (“flail”), from Proto-West Germanic flagil, of uncertain origin. Cognate with Scots flail (“a thresher's flail”), West Frisian fleil, flaaiel (“flail”), Dutch vlegel (“flail”), German Flegel (“flail”). Possibly a native Germanic word from Proto-Germanic flagilaz (“whip”), from Proto-Germanic flag-, flah- (“to whip, beat”), from Proto-Indo-European pleh₂k- (“to beat, hit, strike; weep”); compare Old Norse flaga (“sudden attack, bout”), Lithuanian plàkti (“to whip, lash, flog”), Ancient Greek πληγνύναι (“strike, hit, encounter”), Latin plangō (“lament”, i.e. “beat one's breast”) + Proto-Germanic -ilaz. If so, related also to flag, flack, flacker. Alternatively, flagil may be an early borrowing of Latin flagellum (“winnowing tool, thresher”), diminutive of flagrum (“scourge, whip”), from Proto-Indo-European bʰlag-, bʰlaǵ- (“to beat”); compare Old Norse blekkja (“to beat, mistreat”). Compare also Old French flael (“flail”), wa flayea (“flail”) (locally pronounced "flai"), Italian flagello (“scourge, whip, plague”).
Etymology from Wiktionary, CC BY-SA
Practised in A Song of Ice and Fire