twitch (v.) Look up twitch at Dictionary.com
late 12c., to-twic-chen "pull apart with a quick jerk," related to Old English twiccian "to pluck," from Proto-Germanic *twikjonan (cf. Low German twicken, Dutch twikken, Old High German gizwickan, German zwicken "to pinch, tweak"). Related: Twitched; twitching. The noun is attested from 1520s.