flail

A tool used for threshing, consisting of a long handle with a shorter stick attached with a short piece of chain, thong or similar material.

A weapon which has the (usually spherical) striking part attached to the handle with a flexible joint such as a chain.

To beat using a flail or similar implement.

To wave or swing vigorously

To thresh.

To move like a flail.

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