'Unbeknown' definitions:

Definition of 'unbeknown'

From: WordNet
adverb
Without someone's knowledge; "unbeknownst to me, she made all the arrangements" [syn: unbeknown, unbeknownst]
adjective
(usually used with `to') occurring or existing without the knowledge of; "a crisis unbeknown to me"; "she had been ill for months, unbeknownst to the family" [syn: unbeknown(p), unbeknownst(p)]

Definition of 'Unbeknown'

From: GCIDE
  • Unbeknown \Un`be*known"\, a. Not known; unknown. [Colloq.] [1913 Webster]