I. flail 1 /fleɪl/ BrE AmE verb
1 . [intransitive and transitive] to wave your arms or legs in an uncontrolled way:
He flailed wildly as she tried to hold him down.
flail around/about
James flailed about in the shallow water.
2 . [transitive] to beat someone or something violently, usually with a stick
3 . [intransitive and transitive] to beat grain with a flail
II. flail 2 BrE AmE noun [countable]
[ Date: 1000-1100 ; Language: Latin ; Origin: flagellum 'whip, flail' ]
a tool consisting of a stick that swings from a long handle, used in the past to separate grain from wheat by beating it