unheard-of

adjective
un·​heard-of | \ ˌən-ˈhərd-ˌəv How to pronounce unheard-of (audio) , -ˌäv \

Definition of unheard-of

: previously unknown especially : unprecedented moving at unheard-of speeds

First Known Use of unheard-of

1592, in the meaning defined above

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Time Traveler for unheard-of

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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 15 Jun. 2021.

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More Definitions for unheard-of

unheard-of

adjective

English Language Learners Definition of unheard-of

: not known to have existed or happened before : very unusual

unheard-of

adjective
un·​heard-of | \ ˌən-ˈhərd-ˌəv, -ˌäv \

Kids Definition of unheard-of

: not known before an unheard-of invention

More from Merriam-Webster on unheard-of

Thesaurus: All synonyms and antonyms for unheard-of

Nglish: Translation of unheard-of for Spanish Speakers

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