happening or existing without one's knowledgeunbeknownst to me, my mother was planning a party
unbeknownst to me, my mother was planning a party
unknown
unperceived, unrecognized, unsuspectedunaware, unconscious, unmindfulunknowing, unsuspecting, unwittingignorant, unacquainted, unfamiliar
in 1636
英语同义词词典收录了63618条英语词条，基本涵盖了全部常用同义词或反义词的辨析及翻译，是英语学习的有利工具。