Definition of "vacillate"

vacillate

/ˈvæ.sə.leɪt/

verb
third-person singular simple present vacillates, present participle vacillating, simple past and past participle vacillated
1. (intransitive) To sway unsteadily from one side to the other; oscillate.
  Quotations
  Its [the barometer's] normal register in the Paumotus [the Tuamotus] was 29.90, and it was quite customary to see it vacillate between 29.85 and 30.00, or even 30.05; […]
  1910, Jack London, The Heathen
2. (intransitive) To swing indecisively from one course of action or opinion to another.
  Quotations
  Courageous, patriotic, yet vacillating, many of the noblest principles and the purest intentions, men of large possessions and ancient names, under the afflicting circumstances of the times, failed to render service to their unhappy country, but involved themselves in irremediable ruin.
  1842, [anonymous collaborator of Letitia Elizabeth Landon], chapter XXIX, in Lady Anne Granard; or, Keeping up Appearances. […], volume II, London: Henry Colburn, […], page 68
  On the streets of Berlin, Ruth and her compatriots vacillated "between hope and despair."
  2004, Chris Wallace, Character: Profiles in Presidential Courage