Dictionary

unheard–of

adjective un·heard–of \-ˌəv, -ˌäv\

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

Full Definition of UNHEARD-OF

:  previously unknown; especially :  unprecedented <moving at unheard–of speeds>
ADVERTISEMENT

First Known Use of UNHEARD-OF

1592
UNHEARD-OF Defined for Kids

unheard–of

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

Definition of UNHEARD-OF for Kids

:  not known before <an unheard-of invention>

Browse

Next Word in the Dictionary: unhearingPrevious Word in the Dictionary: unheardAll Words Near: unheard-of
How to use a word that (literally) drives some people nuts.
Test your vocab with our fun, fast game
Ailurophobia, and 9 other unusual fears