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vacillate

American  
[vas-uh-layt] / ˈvæs əˌleɪt /

verb (used without object)

  • vacillates,
    present (3rd person singular)
  • vacillated,
    past participle,  past
  • vacillating
    present participle
  1. to waver in mind or opinion; be indecisive or irresolute.

    His tendency to vacillate makes him a poor leader.

    Synonyms:
    hesitate
  2. to sway unsteadily; waver; totter; stagger.

    Synonyms:
    reel
  3. to oscillate or fluctuate.


vacillate British  
/ ˈvæsɪˌleɪt /

verb

  1. to fluctuate in one's opinions; be indecisive

  2. to sway from side to side physically; totter or waver

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Synonym Usage

See waver 1.

Other Word Forms

Derived Forms

Inflected Forms

Participles

Conjugated Forms

Present

Past

Future

Etymology

Origin of vacillate

First recorded in 1590–1600; from Latin vacillātus (past participle of vacillāre “to sway to and fro”); see -ate 1

Explanation

Vacillate means to waver back and forth, unable to decide. You might vacillate between ordering waffles and pancakes at your favorite diner — it’s hard to pick just one when both are so tasty! Something that vacillates sways or fluctuates, often quite unsteadily. So use this verb to describe the staggering motions of a person who has had too much to drink, as well as the opinions of someone who can’t make up her mind. Synonyms include vibrate, hesitate, and waver. A wise Ethiopian proverb advises, "Do not vacillate or you will be left in between doing something, having something, and being nothing.”

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Vocabulary lists containing vacillate

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

A towering outside hitter, he was known for his ability to vacillate between power and finesse.

From Los Angeles Times ● Aug. 28, 2025

The Oscars can often vacillate between insidery navel-gazing and a ho-hum march toward best picture, but occasionally an acceptance speech cuts through the noise with authenticity.

From New York Times ● Mar. 13, 2023

His leadership skills were lackluster, he was not a charismatic or inspiring speaker, he tended to vacillate in decision-making and he struggled to retain the best staffers.

From Salon ● Jul. 24, 2022

We are a nation traumatized into forgetting, psyches so pulverized by mass death that we vacillate wildly between rage and numbness—waiting until the cycle begins again, so frequent it masquerades as normalcy.

From Slate ● May 25, 2022

His yellow eyes vacillate between me and Autumn.

From "Kwame Crashes the Underworld" by Craig Kofi Farmer

But Bruni easily could have been talking about Sacred Heart Hospital, whose staff vacillates between bridging the compassion gap between medical professionals and patients and managing our expectations.

From Salon ● Feb. 26, 2026

It is closer to music than epic, a mesmerizing suite of songs that conveys Tennyson’s private sorrow as he vacillates from unbearable agony to precarious hope.

From The Wall Street Journal ● Feb. 20, 2026

The rhythmic language vacillates widely between insistent pulse and total freedom.

From New York Times ● Jun. 9, 2022

But it wouldn’t be a reach to believe the NBA legend’s criticism of his portrayal in the show — as a tempestuous and profane malcontent who vacillates between anger and despair — helped boost ratings.

From Washington Post ● May 15, 2022

Between these ifs he vacillates, swung like a ship on stormy waters, touching heaven and hell.

From The Atlantic Monthly, Volume 2, No. 14, December 1858 by Various

In the 2000s, the company vacillated between a fashion-forward and a basics-focused approach—neither of which helped sales much.

From The Wall Street Journal ● Aug. 23, 2026

Instead, I vacillated between forgetting all about cancer some days and feeling like death was imminent others, and it was hard to predict what would prompt either extreme.

From Slate ● May 6, 2026

His children, Kelly and Jack, vacillated between showering him with affection and berating him for not catering to their whims.

From Salon ● Jul. 24, 2025

It was the first in a series of scary scenes for Brinkley, whose feelings for Joel vacillated between veneration, unconditional love and abject fear.

From Los Angeles Times ● Apr. 29, 2025

My love for him vacillated from one entry to another.

From "Americanized" by Sara Saedi

And throughout her reign, Madonna has lived her inconsistencies, vacillating between opinions and social, spiritual and artistic beliefs of all kinds.

From Salon ● Jul. 8, 2026

They pose the theory that the stock market is vacillating between thematic momentum and macro conditions.

From MarketWatch ● Jun. 15, 2026

Oppenheimer modulates the lighting during the scenes from cool to warm and back again, underlining the vacillating feelings they can’t acknowledge outright.

From New York Times ● Dec. 5, 2024

We hate vacillating on matters of major consequence.

From Seattle Times ● Jan. 14, 2024

Jam could see a whole river of things in his face, currents shifting and swelling, vacillating from grief to fury.

From "Pet" by Akwaeke Emezi

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