flail

noun

1. A tool used for threshing, consisting of a long handle (handstock) with a shorter stick (swipple or swingle) attached with a short piece of chain, thong or similar material.

   “When in one night, ere glimpse of morn, His shadowy flail hath threshed the corn That ten day-labourers could not end;”

   “Huge fragments vaulted like rebounding hail, Or chaffy grain beneath the thresher's flail”

   “On him alone the curse of Cain Fell, like a flail on the garnered grain, And struck him to the earth!”

   “If the farmer must use the spade because he has not capital enough for a plough, the sickle instead of the reaping machine, the flail instead of the thresher...”

2. A weapon which has the (usually spherical) striking part attached to the handle with a flexible joint such as a chain.
3. (often, plural)Part of a rotating device, often used for cutting vegetation.

   “The carriage washing plant uses four pairs of rotating rag flails and will be capable of dealing with the whole of the diesel units as well as steam stock used for main-line trains.”

verb

1. (transitive)To beat using a flail or similar implement.
2. (transitive)To wave or swing vigorously

   “Tangling with Ziv, Cameron caught him with a flailing elbow, causing the Israeli defender to go down a little easily. However, the referee was in no doubt, much to the displeasure of the home fans.”

   “He stopped in his tracks – then, flailing his arms wildly in the air, began to stagger backwards.”

3. (transitive)To thresh.
4. (intransitive)To move like a flail.

   “He was flailing wildly, but didn't land a blow.”

   “Undismayed he continued to flail with the broken half of it, denting many a helmet[.]”