Synonyms and related words :
bob, bobble, bounce, bump, didder, dither, falter, grimace, jar, jerk, jig, jigget, jiggle, jog, joggle, jolt, jostle, moue, mow, pout, quake, quaver, quiver, shake, shiver, shock, shudder, snarl, tic, tremble, tremor, twitch, twitter, wobble, wry face, wry mouth