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an-unknown-quantity

/ən ʌnˈnəʊn ˈkwɒn.ti/
IELTSAcademic
idiom

Something or someone whose value, ability, or result is not yet known. People use it when they cannot judge what will happen, or how good a person or thing is.

  • The new player is still an unknown quantity.
  • This policy is an unknown quantity for businesses.
  • Her reaction was an unknown quantity at the meeting.

Adinary Nuance

An unknown quantity is different from a mystery. A mystery is something hidden and interesting, but an unknown quantity is simply hard to judge. It is also close to unpredictable, but that word describes future behavior more directly. Writers use this phrase when they want a careful, neutral tone.

In other languages

Vietnamese
ẩn số
Spanish
incógnita
Chinese
未知数
Japanese
未知数
Korean
미지수

Etymology

This phrase is from English, built from the words unknown and quantity. It became common in the 19th century to describe something not yet measurable or predictable.

Common phrases

remain an unknown quantitya complete unknown quantitysomething of an unknown quantity

Synonyms

Related words

Frequently asked questions

Is an unknown quantity formal or informal?
It is fairly formal and common in writing, news, and business English.
Can I use an unknown quantity for a person?
Yes. It often describes a person whose ability or behavior is not yet clear.
What is the difference between an unknown quantity and a wildcard?
An unknown quantity is not yet judged. A wildcard is more likely to surprise others.