Synonyms

momentous

American

[moh-men-tuhs] / moʊˈmɛn təs /

adjective

of great or far-reaching importance or consequence.

a momentous day.

Synonyms:

serious, crucial, critical, vital

Antonyms:

trifling, trivial

momentous British

/ məʊˈmɛntəs /

adjective

of great significance

"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

Related Words

See heavy.

Other Word Forms

momentously adverb
momentousness noun
unmomentous adjective
unmomentously adverb
unmomentousness noun

Etymology

Origin of momentous

First recorded in 1645–55; moment + -ous

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.

The administration is at its own-designated fork in the road, with any decision carrying momentous ramifications.

From The Wall Street Journal

The brothers had a momentous year of performances, new music and even a Christmas movie, and 2025 also marked their 20th anniversary as a band.

From Los Angeles Times

Any decisions made could have a potentially momentous impact on questions that determine the future of the region.

From BBC

Each is embarking on a distinct changeover path, but the common denominator of resetting is unmistakable and momentous.

From Barron's

Ahead of the Brussels meeting, EU leaders were keen to stress the momentous nature of the decision.

From BBC

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023