Synonyms of momentous
: having great or lasting importance : consequential, significant
a momentous decision
a momentous event/occasion
The Senate begins a momentous debate on health care today …The New York Times
Deydey usually talked about his travels, the places he'd seen and the people, the close calls and momentous encounters with animals, weather, other Anishinabeg, and best of all, ghosts.Louise Erdrich
The late nineteenth century was strewn with inventions. Many were momentous, but few affected men and women more closely than the bicycle and its motorized offspring: motorcycle, motor-car and aeroplane.Eugen Weber
momentously adverb
a momentously important decision
… a … twist that is executed differently from the comic book story, but is just as dramatically and momentously presented. The Philippines Daily Inquirer
momentousness noun
But other East Europeans had little time to marvel at the momentousness of the moment. Just one day after the fall of the [Berlin] Wall, Bulgaria's dour leader of 35 years, Todor Zhivkov, was ousted. Stephen E. Deane

Examples of momentous in a Sentence

My college graduation was a momentous day in my life. a momentous occasion that will go down in the history books
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.
That momentous draw came in the final group-stage game of the prestigious tournament. Gary Bedore, Kansas City Star, 3 July 2026 At the time, this seemed like the more momentous day, as John Adams wrote in a letter to his wife Abigail on July 3. Harmeet Kaur, CNN Money, 3 July 2026 Hall, a Republican from Weatherford, said the momentous achievement wouldn’t have been possible had the Lord not paved the way. Rachel Royster july 2, Fort Worth Star-Telegram, 2 July 2026 But before either the dialogue with Jeffrey Goldberg or the book discussion, some opening thoughts on this memorable and momentous anniversary. David Frum, The Atlantic, 1 July 2026 See All Example Sentences for momentous

Word History

First Known Use

1631, in the meaning defined above

Time Traveler
The first known use of momentous was in 1631

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Cite this Entry

“Momentous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/momentous. Accessed 7 Jul. 2026.

Kids Definition

momentous

adjective
: very important
a momentous decision
momentously adverb

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