ROGET THESAURUS
Librate
Oscillation
VB
oscillate, vibrate, librate, alternate, undulate, wave, rock, swing, pulsate, beat, wag, waggle, nod, bob, courtesy, curtsy, tick, play, wamble, wabble, dangle, swag, fluctuate, dance, curvet, reel, quake, quiver, quaver, shake, flicker, wriggle, roll, toss, pitch, flounder, stagger, totter, move up and down, bob up and down, pass and repass, ebb and flow, come and go, vacillate, teeter, brandish, shake, flourish.