unknown
Hidden from knowledge
Unknown describes something not known, identified, or recognized.
An unknown caller is unidentified.
An unknown quantity is unmeasured or unpredictable.
The unknown refers to what lies beyond current knowledge or experience: fear of the unknown.
As a noun, an unknown is an unidentified person or thing, or in mathematics, a variable whose value must be determined.
Something hard to fathom
- riddlePuzzling question to solve
- mysterySomething unexplained or unknown
- puzzleChallenge testing ingenuity
- conundrumPerplexing problem or question
cipher · secret · intrigue · cryptic · inscrutable · arcane · esoteric · occult
Without any designation
- unidentifiedNot yet recognized
- facelessLacking identity or features
- incognitoWith identity concealed
- pseudonymFictitious professional name
untraceable · unmarked · unclaimed · unacknowledged · undisclosed · unrevealed · unrecorded · ghostwriter
Not previously known
- alienNon-native being
- foreignFrom another nation
- exoticStrikingly unusual, foreign-seeming
- outlandishStrikingly weird or foreign-seeming
peculiar · odd · bizarre · weird · surreal · unearthly · otherworldly · uncharted
Uncertain of truth
- unpredictableCannot be anticipated
- tentativeUncertain and provisional
- speculativeBased on conjecture
- unsettledNot yet resolved
ambiguous · vague · indefinite · questionable · unconfirmed · unresolved · indeterminate · unsure
enigma
Something hard to fathom
- riddlePuzzling question to solve
- mysterySomething unexplained or unknown
- puzzleChallenge testing ingenuity
conundrum · cipher · secret · intrigue · cryptic · inscrutable · arcane · esoteric · occult · sphinx
nameless
Without any designation
- unidentifiedNot yet recognized
- facelessLacking identity or features
- incognitoWith identity concealed
pseudonym · untraceable · unmarked · unclaimed · unacknowledged · undisclosed · unrevealed · unrecorded · ghostwriter · Jane Doe
unfamiliar
Not previously known
outlandish · peculiar · odd · bizarre · weird · surreal · unearthly · otherworldly · uncharted · unexplored
doubtful
Uncertain of truth
- unpredictableCannot be anticipated
- tentativeUncertain and provisional
- speculativeBased on conjecture
unsettled · ambiguous · vague · indefinite · questionable · unconfirmed · unresolved · indeterminate · unsure · hesitant
variable
Prone to fluctuation
value · coefficient · factor · placeholder · x · y · solve · equation · formula · expression
clue
Solving aid
- whodunitCrime fiction identifying perpetrator
- sleuthPrivate investigator
- detectiveProfessional crime investigator
suspect · case · investigation · thriller · suspense · crime · Sherlock · Agatha · Poirot · Holmes
- spacespace, sun, moon, stars, star
- U-wordsugly, ultimate, ultra, umbrella, unable
- uncertaintyuncertainty, uncertain, unsure, unclear, doubt
- descriptorsnew, novel, original, innovative, modern
- familiarityfamiliar, unfamiliar, acquainted, stranger, recognized
- Frontiersfrontier, border, boundary, edge, borderland
unknownknown
Established as fact
identified · recognized · familiar · discovered · revealed
unknownfamous
Widely known, much recognized
renowned · well-known · celebrated · prominent · eminent
unknownfamiliar
Known from experience
hackneyed · tired · time-honored · conventional · traditional
- the unknownWhat hasn't been discovered
- fear of the unknownDread of unfamiliar things
- unknown callerUnidentified person phoning you
- the great unknownUndiscovered or unknowable realm
- unknown numberQuantity not yet identified
- unknown quantityUndetermined value or factor
unknowing, unknowable, unknowingly, unknowns, unknowledgeable, unknowability, unknown quantity