onmitsu 

noun, plural onmitsu, countable
1) a ninja who is highly trained in the art of ninjutsu and is employed by his lord or the shogunate government
2) a Japanese secret agent whose job is to control public opinion using the Internet
3) a secret moderator of a BBS in Japan

noun, uncountable
4) stealth

No one notices onmitsu.

onmitsu by Amamo-chan January 11, 2006

onitsuka 

Kihachiro Onitsuka was a Japanese soldier who after WWII decided that sports would be good for Japanese youth. He therefore learned how to make shoes circa 1949. He then founded Onitsuka Co Ltd. In 1958 he bought the "Tiger" brand. In 1972 they merged with another company called Jelenk and then they decided they needed a new name. So,they found an old latin phrase that said, "Anima Sana In Corpore Sano"; which means, "A soundmind in a sound body". By taking the first letters of each word in the latin phrase you get ASICS, which is the name of the shoe brand.

Now a days Onitsuka's are used alot by the "scene" or "scenester" subcultures, specifically those consisting of indie and hipster styles.

Man 1: Dude, look at that guy with the onistuka's, that's so hardcore!
Man 2: Scene! Onitsuka's are sooo expensive...

onitsuka by SceneQueen December 23, 2005

Onitsuki 

Onitsuki is a popular IGN (In Game Name). It is popular belief that this name stands for Oni (Devil) Tsuki (Moon) in Japanese, however, the name actually derives from the anime Great Teacher Onitzuka. The name Onitsuki combines the names of the 2 main characters Onitzuka & Fuyutsuki, hence Oni + Tsuki = Onitsuki (like Kim + Kanye = Kimye). The name is an ode to the romance that never happened between the two.

That Onitsuki is bad ass in league of legends....
Didn't Onitsuki used to play on that other WoW server?

Onitsuki by Onituski September 17, 2013