NOT KNOWwithout that person knowing about it 不爲某人所知的
Unbeknown to him, his wife had been trying to phone him all morning.
他哪裏知道,妻子一上午都在給他打電話。
Examples from the Corpus
unbeknown to somebody• Unbeknownst to the public, he was involved in covering up the scandal that was to rock the nation.• Unbeknown to me, Denise had her own plan.