Webster's Revised Unabridged Dictionary · 1913

Vacillate

Vacillate (vas"il*lāt) , intransitive verb

[Latin vacillare, vacillatum; compare Sanskrit vañc.]

1.
To move one way and the other; to reel or stagger; to waver.
[A spheroid] is always liable to shift and vacillatefrom one axis to another. — Paley
2.
To fluctuate in mind or opinion; to be unsteady or inconstant; to waver.