by xxBA115xFreaKyx June 18, 2010

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

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

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

In Oregon Trail II, this term is used when someone in your wagon party dies inexplicably from cholera.
by A Dysentery Germ September 24, 2016

someone who operates a bicycle in dark or low light conditions with no lights or reflectors and usually wearing dark clothing. Ninja cyclists typically ride against traffic and/or on sidewalks in violation of local laws.
(after slamming on brakes) "I didnt even see that ninja cyclist blow that stop sign. I could have hit him"
by Bike Man November 3, 2009
