jitter

名词 jitter:

1. small rapid variations in a waveform resulting from fluctuations in the voltage supply or mechanical vibrations or other sources
2. a small irregular movement

jit.ter

v.intr.（不及物动词）
jit.tered,jit.ter.ing,jit.ters
To be nervous or uneasy; fidget.
紧张或者不安；烦躁
n.（名词）
A jittering movement; a tic.
抽搐，痉挛：紧张不安的动作；抽搐，痉挛
jitters A fit of nervousness. Often used withthe.
jitters 紧张不安：一阵紧张不安。常与定冠词the 连用

来源：
Perhaps alteration of chitter
可能为 chitter的变化