unknown quantity

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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.
See also: quantity, unknown

*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

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

unknown quantity

a person or thing whose nature, value, or significance cannot be determined or is not yet known.
See also: quantity, unknown
References in periodicals archive ?
an unknown quantity of cash, they left the store and possibly fled down an "The staff members were unhurt," said Detective Inspector Sion Williams, of St Asaph CID.
Staff were forced to open the till and the safe before the thieves made off with an unknown quantity of money.
The event takes place from May 27-30 and the four-day format is an unknown quantity.
The Turks open against Brazil tomorrow and while Gunes has done his homework for that one he admits the other two nations - Costa Rica and China - are something of an unknown quantity.
ANOTHER unknown quantity for the Irish, although they will hardly be quaking in their boots at facing the Asian qualifiers - even though they did advance to the last 16 eight years ago in the United States where they were defeated by Sweden.
DESPITE SOME RECENT, heartening development--stateside distribution for two Tsai Ming-liang movies (Vive I'amour [1994] and The Hole [1998]) and Winstar's acquisition of an assortment of Hou Hsiao-hisens (including The Puppetmaster [1993] and Flowers of Shanghai [19981])--Taiwanese cinema is still an unknown quantity in America.
n Verdict: Miss Waters says: "They are an unknown quantity.
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.
An unknown quantity of the Class B drug was seized from the property, but last night police could not confirm how much.
The attacker forced a staff member to the floor and dragged him into an office before taking an unknown quantity of cash.
It will be an advantage to see both the teams as they are an unknown quantity," he said.
The 19-year-old from Aachen is a bit of an unknown quantity having drawn his first contest staged in his hometown in May against 2-2-1 countryman Marcel Gottschalk.
BEST LONGSHOT A forecast outsider who could be primed to outrun its likely odds TOO MUCH TROUBLE is an unknown quantity but could provide an upset in the Group 3 Virgin Money Chester Vase (2.
The thirds took on an unknown quantity in the newly-formed St Margaret's Aigburth Staff side and were given a real test by a team with lots of potential but they edged home 25-13.