未知的,不為人知的
Unbeknown \Un`be*known"\, a. Not known; unknown. [Colloq.]
unbeknown adj : (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)}] adv : without someone's knowledge; "unbeknownst to me, she made all the arrangements" [syn: {unbeknownst}]