unknown quantity

== English == === Pronunciation === === Noun === unknown quantity (plural unknown quantities) (idiomatic) A person or thing whose nature or value is a mystery. Antonyms: known quantity, household name Used other than figuratively or idiomatically: see unknown,‎ quantity. ==== Synonyms ==== blank canvas, enigma ==== See also ==== quesitive === References === “unknown quantity”, in OneLook Dictionary Search.