The amount of inner ninja possessed by an individual.
That guy has so much ninjaness hes almost like Chuck Noris
by w00000000000t December 20, 2005
Can you define these popular missing words?
The act of being a ninja or doing ninja related things, such as jumping building, running with your hands loosely behind you, or climbing up trees and hiding until your "Target" approaches.
He displayed his awesome Ninjaness when he jumped from that K-mart to the Subway.
by Brian the Ninja December 19, 2006