verb intransitiveWord forms: ˈvacilˌlated or ˈvacilˌlating
to waver in mind; show
Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by
Houghton Mifflin Harcourt. All rights reserved.
Word origin of 'vacillate'< L vacillatus, pp. of vacillare, to sway to and fro, waver < IE *wek-, to be bent, prob. < base *wā-, to bend apart, turn > L varus, bent, diverse