[1] : The Collaborative International Dictionary of English v.0.48

vacillate \vac"illate\ va^s"i^ll=at, v. i. imp.  p.
   p. vacillated va^s"i^ll=a`te^d; p. pr.  vb. n.
   vacillating. l. vacillare, vacillatum; cf. skr. va~nc.
   1913 webster
   1. to move one way and the other; to reel or stagger; to
      waver.
      1913 webster

            a spheroid is always liable to shift and
            vacillatefrom one axis to another.    --paley.
      1913 webster

   2. to fluctuate in mind or opinion; to be unsteady or
      inconstant; to waver.
      1913 webster

   syn: see fluctuate.
        1913 webster
see also:
vacillated vacillating fluctuate 

[2] : WordNet (r) 2.0

vacillate
     v 1: be undecided about something; waver between conflicting
          positions or courses of action; "he oscillates between
          accepting the new position and retirement" syn: hover,
           vibrate, oscillate
     2: move or sway in a rising and falling or wavelike pattern;
        "the line on the monitor vacillated" syn: fluctuate, waver
see also:
hover vibrate oscillate fluctuate waver 

[3] : Moby Thesaurus II by Grady Ward, 1.0

104 moby thesaurus words for "vacillate":
   alternate, back and fill, bob, bobble, careen, change, changeable,
   chop and change, coggle, dally, dallying, dangle, demurring,
   dickey, dillydallying, dither, double-minded, doubtful, doubting,
   ebb and flow, eccentric, equivocate, erratic, falter, faltering,
   fickle, fiddle-faddle, flounder, fluctuant, fluctuate, fluctuating,
   flutter, go through phases, halt, halting, hang in doubt,
   hem and haw, hesitant, hesitate, hesitating, inconstant,
   indecisive, insecure, irresolute, librate, lurch, mercurial,
   nutate, oscillate, oscillating, pendulate, pendulous, pitch, reel,
   resonate, ring the changes, rock, roll, rootless, seesaw, shake,
   shaky, shift, shifting, shilly-shally, shilly-shallying, shuffle,
   stagger, stop to consider, swag, sway, swing, teeter,
   teeter-totter, tentative, tergiversate, think twice, timid, toss,
   totter, turn, uncertain, unresolved, unsettled, unstable, unsteady,
   unsure, vacillating, vacillatory, vary, vibrate, volatile, wag,
   waggle, wave, waver, wavering, wax and wane, weak, weak-kneed,
   whiffle, wigwag, wobble, wobbly

Vacillate >> V Words
Vacillate, definition of term: Vacillate
vacillate_pag1.html