Main Entry: un·be·knownst

Pronunciation: \ˌən-bi-ˈnōn(t)st\

Variant(s): also un·be·known \-ˈnōn\

Function: adjective

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

Date: 1636

1 : happening or existing without the knowledge of someone specified —usually used with to <unbeknownst to us rumors were flying>
2 : unknown