Unknown knowns 

Donald Rumsfeld pithy description of an old southern saying.

Rumsfeld says 'unknown knowns', down here we say, 'He's so fucking stupid, not only doesn't he know nothin', he don't even suspect it.'

Unknown knowns by pshaw August 4, 2014

known unknown 

Something that one knows they don't know.

There are known unknowns, that is to say that there are things that we know we don't know. (whiskey tango foxtrot, Donald?)

known unknown by Bushmonkey October 1, 2006

Known unknown 

These are the things that you know you don't know. Coined by Donlad Rumsfeld, former US Secretary of Defense.

Boss: Are you saying we don't know what this project will cost?

You: Yep, it's a known unknown!

Known unknown by seven8521 October 31, 2009