unbeknownst

c. 1636: probably from unbeknown +‎ -st.

• IPA^(key): /ˌʌnbɪˈnoʊnst/

• Audio (General Australian):

  (file)

• Audio (US):

  (file)

unbeknownst (not comparable)

1. (followed by to) Without the knowledge of.

   He went home early, unbeknownst to his mother.

   • 2017 August 27, Brandon Nowalk, “Game Of Thrones slows down for the longest, and best, episode of the season (newbies)”, in The Onion AV Club‎^[1]:

     Theon’s redemption scene convincingly threatens to kill him right there on the beaches of Dragonstone, dying for a good cause unbeknownst to anyone but the rapscallions who watched him die, but at last it swerves into something genuinely heroic.

• unbeknown, unknown