v. & n.
--v.
1. intr. (of the features, muscles, limbs, etc.) move or contract spasmodically.
2 tr. give a short sharp pull at.
--n.
1. a sudden involuntary contraction or movement.
2 a sudden pull or jerk.
3 colloq. a state of nervousness.
4 a noose and stick for controlling a horse during a veterinary operation.
Derivatives:
twitchy adj. (twitchier, twitchiest) (in sense 3 of n.).
Etymology: ME f. Gmc: cf. OE twiccian, dial. twick