Back-line Ninja 

A Mcdonald's employee who lies about having a black belt or any martial arts training other than playing Mortal Combat or watching Bruce Lee films.

Crazy Dave is a Back-line Ninja.

Back-line Ninja by Big ole Bastard July 5, 2009

ninja pirate 

a pirate that is skilled in the arts of ninjary, they can pilfer and slice at the same time. They are terribly sneaking. They have no equals.

That ninja pirate came out of nowhere and slayed 6 people.

ninja pirate by sweet serenity December 7, 2007

ninja looter 

Someone who grabs loot which he/she has not won during a raid.

Doup won the loot, but that bastard Kerb ninja looted it.

ninja looter by Martin January 28, 2005

ninja assassin 

In roleplaying games (especially ones not centred around physical conflict), a character who has been designed expressly to be extremely powerful in a fight and/or extremely stealthy.
The term is frequently used sarcastically, as creating such a character is often a sign that the person doing so still thinks he's playing D&D.

Did you see the new guy's character? He's a complete ninja assassin.

ninja assassin by Whybird June 8, 2004

Ninja Poop 

When a person has to go to the bathroom to poop, although does so in such a short span of time that no one has time to notice

"Dude, I was in the middle of a meeting and felt something coming. I slipped out of the room, took a Ninja Poop, and was back before anyone even noticed I left."

Ninja Poop by skeevemeister October 27, 2011

free pants ninja 

A stealthy, deadly person who sneaks through the night delivering deadly doses of free pants to unsuspecting victims.

Sean was being a free pants ninja last night. What a gaylord.

free pants ninja by roofiecurlz July 6, 2004

ninja 

A ninja is...

1. Right behind you.
2. Japanese.
3. A person who has 1337 skills, an ability to fly, the ability to totally FLIP OUT and cut people's heads off, and the ability to retract their testicles for defensive purposes.

OMG. Is that a ninja or is that Jesus?

ninja by KwokieMonster March 18, 2008