unbeknownst 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: {unbeknown}]