0 a person or a thing whose abilities, powers, or effects are not yet known:
The third candidate for the seat is a relatively unknown quantity.
He shows promise, but he remains an unknown quantity.
One reason for this was probably the universal fear that the legal system was an unknown quantity for ordinary people.
But on other matters of orthography they remain an unknown quantity, still formulating their practices in spelling and capitalization.
An unknown quantity of this material, estimated to be at least as much as that collected, was left on-site.
It involves having faith in a largely unknown quantity, motivated by benevolence or idealism.
This means that an unknown quantity of other material is omitted, and that some (perhaps much) of the wider crucial social and cultural context for music and theatre is lost.
I believe that it will serve them much better than any unknown quantity of banks and coal mines.
The number of houses available was an unknown quantity and the number of children was also an unknown quantity.