vac·​il·​late | \ˈva-sə-ˌlāt \
vacillated; vacillating

Definition of vacillate 

intransitive verb

1 : to waver in mind, will, or feeling : hesitate in choice of opinions or courses

2a : to sway through lack of equilibrium

b : fluctuate, oscillate

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Other Words from vacillate

vacillatingly \ ˈva-​sə-​ˌlā-​tiŋ-​lē \ adverb
vacillator \ ˈva-​sə-​ˌlā-​tər \ noun

Choose the Right Synonym for vacillate

hesitate, waver, vacillate, falter mean to show irresolution or uncertainty. hesitate implies a pause before deciding or acting or choosing. hesitated before answering the question waver implies hesitation after seeming to decide and so connotes weakness or a retreat. wavered in his support of the rebels vacillate implies prolonged hesitation from inability to reach a firm decision. vacillated until events were out of control falter implies a wavering or stumbling and often connotes nervousness, lack of courage, or outright fear. never once faltered during her testimony

Examples of vacillate in a Sentence

She has vacillated on this issue. vacillated for so long that someone else stepped in and made the decision

Recent Examples on the Web

But after spending the past 18 years vacillating between Mexico’s two dominant parties, voters appear increasingly willing to try something else. New York Times, "The Firebrand Leftist Far Ahead in Mexico’s Presidential Polls," 29 June 2018 That invitation — not unlike the Eagles’ — was pulled after a number of players vacillated on attending. Katie Mcinerney,, "LeBron James and Steph Curry agree: NBA champs aren't headed to the White House," 5 June 2018 Atta remains at his post, and his political party — which dominates the security forces and backed Abdullah for president — is vacillating between the two camps. Pamela Constable, Washington Post, "Afghans, fearing more insurgent violence, feel abandoned by struggling government," 11 Feb. 2018 But Aguilera arrived hours late to court, and began to cry while vacillating over the deal. David Ovalle, miamiherald, "Her drunk driving took a beloved principal’s legs. Now she’ll serve five years.," 19 Jan. 2018 Tess constantly vacillates between being excited and disappointed. Olivia Harrison,, "The Wine You Should Drink With The Premiere Episode Of Sweetbitter," 7 May 2018 The mix in the crowd seemed to vacillate between curious surfers from as far south as San Diego, to local farmers speculating about who might invest and buy out the acreage next door as a real estate venture. Alex Wilson, Outside Online, "Kelly Slater's Wave Pool Is the Future. And It's Bleak.," 7 May 2018 As trade war fears continue, the Chinese and U.S. governments vacillate between inflammatory rhetoric and more calming ones. Lucinda Shen, Fortune, "Here's How the China-U.S. Tariff Talks May Already Be Hurting America's Job Growth," 23 Apr. 2018 Throughout the night, the tone vacillated from celebratory to somber as the celebrities came to terms with their platform. Rebecca Farley,, "The 2018 BBMAs Didn't Know What To Do. So, They Did Everything.," 21 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'vacillate.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of vacillate

1597, in the meaning defined at sense 2a

History and Etymology for vacillate

borrowed from Latin vacillātus, past participle of vacillāre "to be unsteady, totter, be weak or inconstant, waver," of uncertain origin

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Statistics for vacillate

Last Updated

19 Oct 2018

Look-up Popularity

Time Traveler for vacillate

The first known use of vacillate was in 1597

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More Definitions for vacillate



English Language Learners Definition of vacillate

: to repeatedly change your opinions or desires


vac·​il·​late | \ˈva-sə-ˌlāt \
vacillated; vacillating

Kids Definition of vacillate

: to hesitate between courses or opinions : be unable to choose

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Comments on vacillate

What made you want to look up vacillate? Please tell us where you read or heard it (including the quote, if possible).


obstinately defiant of authority

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