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

Trump has just vacillated hardest in Kyiv’s favour. —Nick Paton Walsh, CNN Money, 24 Sep. 2025

But the Broncos have vacillated all over the map in efficiency on every down the last two weeks, and have seen their offense come to a screeching fourth-quarter halt in close losses because of it. —Luca Evans, Denver Post, 22 Sep. 2025

Trump calls out political rivals in wide-ranging eulogy Trump vacillated between eulogizing Kirk, celebrating his political achievements, and taking shots at his rivals, including former President Joe Biden. —N'dea Yancey-Bragg, USA Today, 21 Sep. 2025

However, recent editions have vacillated wildly in scorelines. —Tim Ellis, Forbes.com, 18 Sep. 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