1.Of or relating to a ninja being highly skilled in combat, stealth, and covert actions. Most often known for being stealthy and deadly assassins.
2. The ability to perform duties efficiently and without hesitation to the highest level of perfection without detection
3.An action against a person without the victim knowing what hit them
2. The ability to perform duties efficiently and without hesitation to the highest level of perfection without detection
3.An action against a person without the victim knowing what hit them
by Madnass July 10, 2012

(noun) Someone who sneaks rubbish and into their neighbours' bins when their own bins are full. A bin ninja usually comes after a large gathering has filled a houses garbage receptacles. The act generally occurs at night and requires much sneaking about.
(verb) To bin ninja something.
(verb) To bin ninja something.
"Man. That party was epic. What are we going to do with all these empties...the bins are full!"
"No worries man. We'll just bin ninja them into everyone else's bins tonight."
"No worries man. We'll just bin ninja them into everyone else's bins tonight."
by billybobboy June 2, 2014

the act of taking two 15 inch black dildos and tieing them together with a string like nunchucks. while shiving one up your ass you then swing the free dildo around and sneak up behind your partner and hit them with it. thus creating a ninja like expirience.
by The Urban Flame February 23, 2011

To masturbate/fap silently.
Dave: Why is fapping called fapping?
Max: Because fap is the noise it makes.
Dave: I've never heard that before ..., I must be some kind of ninja fapper
Max: Because fap is the noise it makes.
Dave: I've never heard that before ..., I must be some kind of ninja fapper
by honkthedonk January 17, 2013

To ninja poof would be to smoke (marijuana, tobacco, etc.) while hidden, usually very near people. Bushes work well.
by Cordmeister July 8, 2010

When you send someone a naked picture of themselves that they don't know you took. Especially useful as a pick-up technique.
"Dude, Anna just sent me a ninja sext!!"
"What do you mean?"
"She just sent me a picture of MY penis, but I've never been naked in front of her? WTF??"
"True ninja broseph. She's a ninja sext master."
"What do you mean?"
"She just sent me a picture of MY penis, but I've never been naked in front of her? WTF??"
"True ninja broseph. She's a ninja sext master."
by Ninjasextmaster69 August 7, 2011

by xxBA115xFreaKyx June 18, 2010
