writhe (v.)

Old English wriðan (transitive) "to twist or bend," earlier "to bind or fetter," from Proto-Germanic *writhanan (source also of North Frisian wrial, Old High German ridan, Old Norse riða, Middle Swedish vriþa, Middle Danish vride), from PIE *wreit-, from root *wer- (2) "to turn, bend." Intransitive, of the body or limbs, "move in a twisting or tortuous manner," from c. 1300. Related: Writhed; writhing.