Merriam-Webster's Collegiate® Dictionary, 11th Edition
JERK
I. noun
Etymology: probably alteration of yerk
Date: 1575
a single quick motion of short duration,
2. jolting, bouncing, or thrusting motions, a tendency to produce spasmodic motions,
3. an involuntary spasmodic muscular movement due to reflex action, involuntary twitchings due to nervous excitement,
4. an annoyingly stupid or foolish person, an unlikable person, the pushing of a weight from shoulder height to a position overhead in weight lifting,
II. verb
Date: 1589
transitive verb to give a quick suddenly arrested push, pull, or twist to, to propel or move with or as if with a quick suddenly arrested motion, to mix and serve (as sodas) behind a soda fountain, intransitive verb to make a sudden spasmodic motion, to move in short abrupt motions or with frequent jolts, jerker noun
III. transitive verb
Etymology: back-formation from 1jerky
Date: 1707
to preserve (meat) in long sun-dried slices