Third-person singular simple present indicative form of flail.(verb)
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Use "flails" in a sentence
"The flails were the simplest of instruments, and were always seen with the same accompaniment -- the interior of a barn."
"Every individual composing that mob carried some weapon calculated for defence, such as flails, scythes, sickles, bludgeons, &., and this mode of arming caused them to wear a most formidable appearance; while the passion that superstition had called up was strongly depicted in their inflamed features."
"Whips: May also be called flails, floggers, and cat o’ nines."