- 1 [intransitive, transitive] flail (something) (around) to move around without control; to move your arms and legs around without control The boys flailed around on the floor. He was running along, his arms flailing wildly.
- 2[transitive] flail somebody/something to hit someone or something very hard, especially with a stick
NAmE//fleɪl//Verb Forms present simple I / you / we / they flail
he / she / it flails
past simple flailed
-ing form flailing