Definition of unknown quantity
: someone or something whose abilities or characteristics are not yet known If you've never been published before, you're an unknown quantity, so you're going to have difficulty selling your first novel.
Word by Word Definitions
: not known or not well-known
: having an unknown value
: one that is not known or not well-known
: a person who is little known (as to the public)
: something that requires discovery, identification, or clarification: such as
: an indefinite amount or number
: a determinate or estimated amount
: total amount or number
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