- flailA 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.
- flagellumIn protists, a long, whiplike membrane-enclosed organelle used for locomotion or feeding.
- flagelliformshaped like a whip
- flagellistOne who administers punishment by whipping.