unknown unknown

== English == === Etymology === Popularized by Donald Rumsfeld in 2002, though used much earlier. === Noun === unknown unknown (plural unknown unknowns) An uncertainty of unknown magnitude, consequence, structure, and probability characteristics, possibly with completely unsuspected existence; something that we don't know that we don't know. ==== Synonyms ==== unk-unk ==== Related terms ==== known known known unknown unknown known === See also === a little knowledge is a dangerous thing