1. (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
1. without someone's knowledge
- unbeknownst to me, she made all the arrangements
Similar word(s): unbeknown
Sentences with unbeknownst as an adverb:
- He went home early, unbeknownst to his mother.