unfathomable

adjective

un·​fath·​om·​able ˌən-ˈfa-t͟hə-mə-bəl How to pronounce unfathomable (audio)
: not capable of being fathomed:
b
: impossible to comprehend
unfathomably adverb

Examples of unfathomable in a Sentence

His behavior is completely unfathomable. the unfathomable reaches of space
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.
Besting five runs would’ve been unfathomable for Toronto last week. Mitch Bannon, New York Times, 31 May 2025 Books, Arts & Manners Books The Second World War’s Masters and Commanders Rich Lowry The choices and predilections of leaders can bring national triumph, or catastrophe and unfathomable suffering. Mary Katharine Ham, National Review, 17 Apr. 2025 We have been supported by an unfathomable number of beings who have come before us, from generations of ancestors to animals and plants that sustained all life on our planet since its creation. Gary Stoller, Forbes.com, 15 Apr. 2025 The Mavericks’ unfathomable decision to ship out the future Hall of Famer helped rev up the ratings in the latter portion of the season, as league-wide deliveries following the trade deadline jumped 16%. Anthony Crupi, Sportico.com, 15 Apr. 2025 See All Example Sentences for unfathomable

Word History

First Known Use

1640, in the meaning defined above

Time Traveler
The first known use of unfathomable was in 1640

Browse Nearby Words

Cite this Entry

“Unfathomable.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unfathomable. Accessed 8 Jun. 2025.

Kids Definition

unfathomable

adjective
un·​fath·​om·​able ˌən-ˈfat͟h-ə-mə-bəl How to pronounce unfathomable (audio)
: not capable of being fathomed:
b
: impossible to understand

More from Merriam-Webster on unfathomable

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!