From The Collaborative International Dictionary of English v.0.48 [gcide]:
Vacillation \Vac`il*la"tion\, n. [L. vacillatio: cf. F.
vacillation.]
1. The act of vacillating; a moving one way and the other; a
wavering.
[1913 Webster]
His vacillations, always exhibited most pitiably in
emergencies. --Macaulay.
[1913 Webster]
2. Unsteadiness of purpose; changeableness.
[1913 Webster]
There is a vacillation, or an alternation of
knowledge and doubt. --Jer. Taylor.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
vacillation
n 1: indecision in speech or action [syn: hesitation,
vacillation, wavering]
2: changing location by moving back and forth [syn: swing,
swinging, vacillation]