unbeknown
Outside one's knowledge
Unbeknown means without someone's knowledge: Unbeknown to her parents, she had been skipping school for weeks.
The word almost always appears in the phrase "unbeknown to," indicating that something happened or exists without a particular person being aware.
Unbeknownst is a variant with identical meaning, slightly more common in American English.
Lacking any awareness
- unknowingLacking awareness or information
- unsuspectingNot anticipating danger
- ignorantLacking knowledge or awareness
- uninformedLacking necessary knowledge
clueless · unconscious · blind · unacquainted · unfamiliar · unwitting · in the dark · none the wiser
Made invisible deliberately
- covertIntentionally concealed
- undetectedNot discovered yet
- invisibleCannot be seen
- obscuredMade hard to perceive
veiled · latent · buried · shrouded · cloaked · masked · undercover · clandestine
Meant to stay secret
- classifiedRestricted from disclosure
- undisclosedNot made known
- privateRestricted to certain parties
- hush-hushHighly confidential matter
under-the-table · backdoor · furtive · surreptitious · stealthy · cloak-and-dagger · privy · discreet
Not anticipated beforehand
- suddenOccurring without prior notice
- unforeseenNot predicted or expected
- unanticipatedNot predicted beforehand
- shockingCausing intense surprise
startling · revelation · bombshell · eye-opener · curveball · out of the blue · bolt from the blue · catch off guard
oblivious
Lacking any awareness
- unknowingLacking awareness or information
- unsuspectingNot anticipating danger
- ignorantLacking knowledge or awareness
uninformed · clueless · unconscious · blind · unacquainted · unfamiliar · unwitting · in the dark · none the wiser · heedless
concealed
Made invisible deliberately
- covertIntentionally concealed
- undetectedNot discovered yet
- invisibleCannot be seen
obscured · veiled · latent · buried · shrouded · cloaked · masked · undercover · clandestine · camouflaged
confidential
Meant to stay secret
- classifiedRestricted from disclosure
- undisclosedNot made known
- privateRestricted to certain parties
hush-hush · under-the-table · backdoor · furtive · surreptitious · stealthy · cloak-and-dagger · privy · discreet · nonpublic
unexpected
Not anticipated beforehand
- suddenOccurring without prior notice
- unforeseenNot predicted or expected
- unanticipatedNot predicted beforehand
shocking · startling · revelation · bombshell · eye-opener · curveball · out of the blue · bolt from the blue · catch off guard · blindside