unbeknownst

adjective

un·​be·​knownst ˌən-bi-ˈnōn(t)st How to pronounce unbeknownst (audio)
variants or less commonly unbeknown
Synonyms of unbeknownst
1
: happening or existing without the knowledge of someone specified
usually used with to
unbeknownst to us rumors were flying
2

Did you know?

For reasons unbeknownst to perhaps all of us, unbeknownst is a word in good standing. It has the ring of a true archaism, what with that -st ending we know from such Shakespearean gems as “thou dost snore distinctly,” and yet it is not what it seems; unbeknownst may resemble archaic verb forms like dost and canst, but it’s just playing dress-up. To authentically use dost and canst one has to be addressing someone else, and no one has ever said “thou unbeknownst,” or even “thou beknownst.” Beknown, which had some meager use between the 16th and 19th centuries, was a form of the verb beknow (in use between the 14th and 16th centuries) but was mostly used as an adjective meaning “known, familiar.” If anything would get the -st ending, it would be beknow, and the form would be beknowst or beknowest. All this to say, when unbeknownst started cropping up in fictional dialogue in the early decades of the 19th century, the word did not please everyone. By the early 20th century, it was being disparaged as “a vulgar provincialism” and a term “out of use except in dialect or uneducated speech.” The slander has done no good whatsoever. Unbeknownst is perfectly standard today, even in formal prose. Note that speakers of British English prefer unbeknown, which lacks that unjustified -st and is 200 years older. Perhaps our friends across the pond beknow more than we do.

Synonyms of unbeknownst

Examples of unbeknownst in a Sentence

unbeknownst to me, my mother was planning a party
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.
In the eight-part audio drama Babalu, Sherry Zhang died by suicide in 1989, leaving behind a baby daughter Luisa and, unbeknownst to her family, dozens of cassette tapes recording her innermost thoughts. Ryan Lattanzio, IndieWire, 21 Apr. 2026 But unbeknownst to her, each of the Blisses have a guest of their own arriving at the very same time. Ellise Shafer, Variety, 17 Apr. 2026 All unbeknownst to her, while she's been essentially disconnected from life while performing standup at a casino in Singapore. Gerrad Hall, Entertainment Weekly, 10 Apr. 2026 While passengers, for the most part, do their best to extend common courtesy to airline staff, there’s one boarding habit that, unbeknownst to passengers, grinds the gears of flight attendants who are preparing for departure. Joey Skladany, Travel + Leisure, 9 Apr. 2026 See All Example Sentences for unbeknownst

Word History

Etymology

un- entry 1 + obsolete English beknown known; unbeknownst, irregular from unbeknown

First Known Use

1636, in the meaning defined at sense 1

Time Traveler
The first known use of unbeknownst was in 1636

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Cite this Entry

“Unbeknownst.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unbeknownst. Accessed 28 Apr. 2026.

Kids Definition

unbeknownst

adjective
un·​be·​knownst ˌən-bi-ˈnōn(t)st How to pronounce unbeknownst (audio)
variants also unbeknown
: happening without one's knowledge : unknown
events unbeknownst to me

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