Word of the Day:

: happening or existing without the knowledge of someone specified

Unbeknownst to Caroline, we all chipped in to have a large bouquet of flowers delivered to her office for her birthday.

"Although his wife was well aware of their excessive spending habits, Travis was the one who paid the bills-and he often used credit cards to cover them unbeknownst to Vonnie." - From an article by Penny Wrenn on Forbes.com, October 9, 2013

More example sentences

"Unbeknownst" derives from "beknown," an obsolete synonym of "known." But for a word with a straightforward history, "unbeknownst" and its older and less common variant "unbeknown" have created quite a flap among usage commentators. Despite widespread use (including appearances in the writings of Charles Dickens, A.E. Housman, and E.B. White), the two words have been called everything from "obsolete" to "vulgar." Our evidence, however, shows that both can be considered standard.