unheard-of

adjective

un·​heard-of ˌən-ˈhərd-ˌəv How to pronounce unheard-of (audio)
-ˌäv
: previously unknown
especially : unprecedented
moving at unheard-of speeds

Examples of unheard-of in a Sentence

houses selling at unheard-of prices
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.
Google claims Gemini Diffusion is capable of previously unheard-of accuracy in complex math and coding. Ryan Whitwam, ArsTechnica, 20 May 2025 Furthermore, a whopping nine shapes and sizes are available, a virtually unheard-of smorgasbord of options for sleeping bags, and part of REI’s admirable efforts to share the outdoors with anyone and everyone. Drew Zieff, Outside Online, 16 May 2025 Opened in 1896 by railroad and oil tycoon Henry Flagler, the grand oceanfront resort has remained privately owned by his descendants for 129 years—an almost unheard-of legacy among large-scale historic hotels. Skye Sherman, Southern Living, 15 May 2025 Related article First image from the world’s largest solar telescope captures the sun in unheard-of detail Astronomers observed a collision between two neutron stars in 2017. Ashley Strickland, CNN Money, 3 May 2025 See All Example Sentences for unheard-of

Word History

First Known Use

1592, in the meaning defined above

Time Traveler
The first known use of unheard-of was in 1592

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Cite this Entry

“Unheard-of.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unheard-of. Accessed 5 Jun. 2025.

Kids Definition

unheard-of

adjective
un·​heard-of
-ˌəv,
-ˌäv
: previously unknown : unprecedented
moving at unheard-of speeds

More from Merriam-Webster on unheard-of

Last Updated: - Updated example sentences
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