unknown

not known

• “an unknown amount”
• “an unknown island”
• “an unknown writer”
• “an unknown source”

being or having an unknown or unnamed source

• “a poem by an unknown author”
• “corporations responsible to nameless owners”
• “an unnamed donor”

not known to exist

• “things obscurely felt surged up from unsuspected depths in her” Edith Wharton

not famous or acclaimed

• “an obscure family”
• “unsung heroes of the war”

not known before

• “used many strange words”
• “saw many strange faces in the crowd”
• “don”

an unknown and unexplored region

• “they came like angels out the unknown”

anyone who does not belong in the environment in which they are found

a variable whose values are solutions of an equation