A person who hides how much of a nerd he is by acting normal majority of the time. Only his closest friends know how much of a nerd he is while others are unaware.
Joel is such a ninja nerd, he acts normal but we know he's a huge geek deep down.
ayon kay poiboyJ ika-23 ng Hulyo, 2008
1 more definition
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"
ayon kay Mo Hat ika-07 ng Hunyo, 2005