unknown quantity

Also found in: Dictionary, Thesaurus, Acronyms.

an unknown quantity

A person or thing that is unpredictable and thus difficult to anticipate. We're still revising our new product, so its potential success is an unknown quantity. This is her first year teaching, so her ability to connect with her students is still an unknown quantity. I missed that guy's audition, so he's still an unknown quantity to me as a guitar player.
See also: an, quantity, unknown
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.

*unknown quantity

Fig. a person or thing about which no one is certain. (*Typically: be ~; become ~.) John is an unknown quantity. We don't know how he's going to act. The new clerk is an unknown quantity. Things may not turn out all right.
See also: quantity, unknown
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

unknown quantity

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.
See also: quantity, unknown
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

unknown quantity

a person or thing whose nature, value, or significance cannot be determined or is not yet known.
See also: quantity, unknown
Farlex Partner Idioms Dictionary © Farlex 2017
See also:
References in periodicals archive ?
estimated the use of 24 gallons diesel fuel for their excavators and an unknown quantity of fuel for transportation of debris, equipment and laborers.
Her nomination presents a largely unknown quantity to the Senate for confirmation.
Just moved from the Federal Reserve Board to chair the Council of Economic Advisers, Ben Bernanke is an unknown quantity to his new colleagues.
Organisak, a Pittsburgh native, is hardly an unknown quantity at the PDC.
Barrow is even more of an unknown quantity, but has also impressed Wrexham with efficient work he has done during spells with Wigan and Chester.
They know what they can do, but they are an unknown quantity to others.
A new CEO means that everyone in the organization, with the exception of executive secretaries, is in the same position as any new hire: an unknown quantity who has to prove he or she can and will do what the CEO wants, the way the CEO wants it done.
Among these collections were The Ruling Passion (1901), The Blue Flower (1902), The Unknown Quantity (1912), The Valley of Vision(1919), and The Golden Key (1926).
For years, cosmologists have debated whether the amount of mass in the universe -- still an unknown quantity -- is more likely to favor the first scenario or the second.
One limitation of putting fluff back into an extruder with conventional in-line recylcing systems is that the fluff is an unknown quantity and cannot be calculated precisely.
Her other novels include The Dark Garden (1933), The Glass Slipper (1938), The Sisters (1944), Five Passengers from Lisbon (1946), Never Look Back (1951), Unknown Quantity (1953), Man Missing (1954), Melora (1959), Jury of One (1960), Run Scared (1963), Witness at Large (1966), Murder in Waiting (1973), The Patient in Cabin C (1983), and A Fighting Chance (1986).
The pair stole an unknown quantity of cash before fleeing shortly before 10pm on Saturday.
They threatened staff in the store and made off with an unknown quantity of cash.
He arrived as a bit of an unknown quantity to many people but leaves us having made a real impression on the club."