jit·ter / ˈjitər/ inf. • n. 1. (jitters) feelings of extreme nervousness: a bout of the jitters. 2. slight irregular movement, variation, or unsteadiness, esp. in an electrical signal or electronic device.• v. [intr.] act nervously: an anxious student who jittered at any provocation. ∎  (of a signal or device) suffer from jitter.DERIVATIVES: jit·ter·i·ness / -rēnis/ n.jit·ter·y adj.

jitter The variations in the arrival time of a supposedly synchronous signal. Jitter may be caused by the fact that the original source of the signals has variations from its ideal periodic time, or by variations in the transit time from the signal source to the point at which the arrival times are actually observed, caused either by variations in the pathlength or in the speed at which the signal travels. In practice it is likely that all three effects contribute, and jitter is nearly always present.

jitter (U.S.) act in a nervous way. XX.
So jitters sb. pl., jittery XX. of unkn. orig.