adj.
Unbeknown.
adv.
Without the knowledge of a specified party. Used with to: Our cousin had been ill for years, unbeknownst to the family.
[UNBEKNOWN + -st (as in AMONGST).]
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
