vacillate

verb

vac·​il·​late ˈva-sə-ˌlāt 

vacillated; vacillating

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 

adverb

vacillator

ˈva-sə-ˌlā-tər 

noun

Synonyms

• hesitate
• falter

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

Lawsuits have followed many of these funding actions, and the subsequent back-and-forth legal battles have left some grants vacillating between canceled and reinstated. —Evan Bush, NBC news, 26 Aug. 2025

If a company is looking to add on to its portfolio or functions, acquiring the other business sooner rather than later allows for more definitive forecasting—and more stability if the markets vacillate on White House policy pronouncements. —Megan Poinski, Forbes.com, 19 Aug. 2025

The president vacillates from one position to another, discarding policies like gloves—a cease-fire one day and a comprehensive settlement the next, with threats of disengagement along the way. —Michael Kimmage, Foreign Affairs, 19 Aug. 2025

This week, Trump's public statements have vacillated between close alignment with Ukraine and Europe and talking about the war in terms more sympathetic to Russia and Putin. —Tamara Keith, NPR, 14 Aug. 2025

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

Rhymes for vacillate

• abdicate
• abrogate
• acetate
• activate
• actuate
• adsorbate
• aggravate
• agitate
• alginate
• alienate
• allocate
• amputate

Kids Definition

vacillate

verb

vac·​il·​late ˈvas-ə-ˌlāt 

vacillated; vacillating

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

vacillation

ˌvas-ə-ˈlā-shən

noun

vacillator

ˈvas-ə-ˌlāt-ər 

noun