yerk

v. t.

  1. To throw or thrust with a sudden, smart movement; to kick or strike suddenly; to jerk.
  2. To strike or lash with a whip.

v. i.

  1. To throw out the heels; to kick; to jerk.
  2. To move a quick, jerking motion.

n.

  1. A sudden or quick thrust or motion; a jerk.