These are things that you don't know that you don't know, as opposed to things that you know you don't know. Coined by Donlad Rumsfeld, former US Secretary of Defense.
Boss: Is there anything that will cause this systemimplementation to fail?
You: That's an unknown unknown!
an unknown artist is an unheard of yet a highly underrated and slept on public figure or artist that the world lacks the knowledge to learn about or appreciate
Ergo, junior Grimes = unknown artist
Or artist unknown, either way the outcome is the same
When you have to pee in a movie but don’t want to miss anything, and must do the following mental equation: will the amount I have to pee cause enough discomfort to diminish my attention capacity for the remainder of the movie to an extent which is greater than the amount of the movie I would miss by making a mad dash to the restroom.
I saw Satantango last night, wonderful film but by the 5th hour I had to start doing pee calculus.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).