vacillate

verb

vac·​il·​late ˈva-sə-ˌlāt How to pronounce vacillate (audio)
vacillated; vacillating
Synonyms of vacillate

intransitive verb

1
: to waver in mind, will, or feeling : hesitate in choice of opinions or courses
2
a
: to sway through lack of equilibrium
b
: fluctuate, oscillate
vacillatingly
ˈva-sə-ˌlā-tiŋ-lē How to pronounce vacillate (audio)
adverb
vacillator
ˈva-sə-ˌlā-tər How to pronounce vacillate (audio)
noun

Synonyms of vacillate

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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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Then there are the fragmented attention spans birthed by our dearly beloved screens, which cultivate a kind of cognitive whiplash that vacillates between amnesia and yearning for more. — Christopher Coffman, The Conversation, 24 Aug. 2026 Ellison and his executives have vacillated from anger to acceptance. — Meg James, Los Angeles Times, 12 Aug. 2026 Since then, his game behind the plate has vacillated between good and bad — an inconsistency aggravated by the presence of Luis Torrens (and his defensive excellence) as his backup. — Tim Britton, New York Times, 4 Aug. 2026 This is someone who vacillates between different ways of being. — Hunter Ingram, Variety, 1 Aug. 2026 See All Example Sentences for vacillate

Word History

Etymology

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

First Known Use

1597, in the meaning defined at sense 2a

Time Traveler
The first known use of vacillate was in 1597

Rhymes for vacillate

See All Rhymes for vacillate

Browse Nearby Words

vacillant
vacillate
vacillatingly
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Cite this Entry

“Vacillate.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/vacillate. Accessed 1 Sep. 2026.

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Kids Definition

vacillate

verb
vac·​il·​late ˈvas-ə-ˌlāt How to pronounce vacillate (audio)
vacillated; vacillating
: to hesitate between courses or opinions : be unable to choose
vacillation
ˌvas-ə-ˈlā-shən
noun
vacillator
ˈvas-ə-ˌlāt-ər How to pronounce vacillate (audio)
noun
Last Updated: - Updated example sentences
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