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

The global economy has for months been roiled by a tit-for-tat of mounting tariffs, export controls and other penalties hitting areas from high-tech goods to high-seas shipping, as the US and China have vacillated between escalation and negotiation. —Betsy Klein, CNN Money, 30 Oct. 2025

By the end of March 2018 Aydın seemed unsure whether to try to clear his name or lay low, vacillating between the two strategies. —Moisés Naím, Literary Hub, 27 Oct. 2025

The actress' create a world that engulfs you into their faux-showbusiness drama, a world of women vacillating between supporting each other and backstabbing to get themselves ahead, with striking performances that led to Oscar nominations for Davis, Ritter, Holm and Baxter. —Angela Andaloro, PEOPLE, 27 Oct. 2025

Striking the right balance between freedom for adults and safety for users has been a difficult balancing act for OpenAI, which has vacillated between permissive and restrictive chat content controls over the past year. —ArsTechnica, 15 Oct. 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