A ninja who is in touch with his nerdy side. You cannot have a female ninjanerd, only male, although they may have feminine characteristics. Used to insult a person who believes he's a ninjanerd, but is a nerd at the same time, the nerd part using the computer freqeuently, the ninja part being stealthy.
"Hah, I am a ninja! But I love downloading this anime and using the computer and chatting on IRC"