unknown

1. (sometimes postpositive) Not known; unidentified; not well known.Examples: "The Celebrity, by arts unknown, induced Mrs. Judge Short and two other ladies to call at Mohair on a certain afternoon when Mr. Cooke was trying a trotter on the track. The three returned wondering and charmed with Mrs. Cooke; they were sure she had had no hand in the furnishing of that atrocious house."; "I suspect that this large and complex military railway system, shrouded in official secrecy for most of its operational life, remains unknown to many people."Synonyms: anonymous, unfamiliar, uncharted, undiscovered, unexplored, unidentified, unnamed, unrecognizedAntonyms: well-known, famous, knownpostpositionalsometimes