unknown quantity

Discover More

Idioms and Phrases

An unpredictable person or thing, as in We don't know how the new pitcher will do—he's an unknown quantity . This expression comes from algebra, where it signifies an unknown numerical value. Its figurative use dates from the mid-1800s.

Related Words

also-ran
long shot
sleeper
underdog

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

unknown Unknown Soldier

Browse