UNKNOWN
nameless, unidentified, unknown, unnamed
(adjective) being or having an unknown or unnamed source; “a poem by an unknown author”; “corporations responsible to nameless owners”; “an unnamed donor”
strange, unknown
(adjective) not known before; “used many strange words”; “saw many strange faces in the crowd”; “don’t let anyone unknown into the house”
obscure, unknown, unsung
(adjective) not famous or acclaimed; “an obscure family”; “unsung heroes of the war”
unknown
(adjective) not known; “an unknown amount”; “an unknown island”; “an unknown writer”; “an unknown source”
unknown
(adjective) not known to exist; “things obscurely felt surged up from unknown depths”
unknown, unknown quantity
(noun) a variable whose values are solutions of an equation
unknown, unknown region, terra incognita
(noun) an unknown and unexplored region; “they came like angels out the unknown”
stranger, alien, unknown
(noun) anyone who does not belong in the environment in which they are found
Source: WordNet® 3.1
Etymology
Adjective
unknown (comparative more unknown, superlative most unknown)
(sometimes postpositive) Not known; unidentified; not well known.
Synonyms: anonymous, unfamiliar, uncharted, undiscovered, unexplored, unidentified, unnamed, unrecognized, unrevealed, unascertained, obscure, unsung
Antonyms: well-known, famous, known
Noun
unknown (plural unknowns)
(algebra) A variable (usually x, y or z) whose value is to be found.
Any thing, place, or situation about which nothing is known; an unknown fact or piece of information.
A person of no identity; a nonentity
Verb
unknown
past participle of unknow
Source: Wiktionary
Un*known", a.
Definition: Not known; not apprehended.
– Un*known"ness, n. [R.] Camden.
Source: Webster’s Unabridged Dictionary 1913 Edition