Ninja whinger

Someone that complains by stealth in order to undermine their victims.
A person that uses something you've told them in confidence to get at you behind your back.
Someone that deliberately puts shit on you for personal gain.

Heads up man, that mofo is a ninja whinger - don't tell him shit.

Ninja whinger by KR00ZZ July 8, 2012

ninja tech 

Some sort of Ninja move that saves the day... Specifically while making glass art on a torch.

Bang! -ninja tech

ninja tech by ework February 21, 2013

ninja beat 

The act of silently masturbating while in the same bed as your significant other, likely while they are asleep.

My girl didn't want to give me head during her period week, so I had to pull off the ninja beat several times.

ninja beat by Arjiff January 8, 2014

Ninja squirtle

A stealthy shart that sneaks up on you without warning.

I was on my way to the bar when *BAM*, Ninja Squirtle attack.

Ninja squirtle by L0L0 June 9, 2015

Ninja aggressive 

its like aggressive (in the passive aggressive sense) but you dont know theyre being aggressive. ....sneaky aggressive.

not to be confused with passive aggressive

Like some farts (silent but deadly)

Im aggressive, but you dont know its happening. Im like ninja aggressive.

Ninja aggressive by edudnikihc August 1, 2016

Ninja Mission 

When you do something you know you're not supposed to do (whether it's good or not so good) or when you do something that other people (like your parents) don't want you to do.

Well...sneaking out to Caid's party at 11 p.m. was a real ninja mission.

Ninja Mission by avtor17 February 7, 2018

ninja handy 

The act of receiving discreet pleasure in from a partners hand under a blanket, coat or table.

Dude, we were watching movies at Stacy’s place last night and she totally gave me a ninja handy with her sister in the room.

ninja handy by Listerfiend May 18, 2018