Comes from the german word for no (nine)
nine can also be used in the place of niner
At first was used mainly by scros, but now almost everyone uses it.
Scro 2: Shob, Niner, i wish!
Person 1: hey do you have the latin homework?
Person 2: niner
Person 1: duuuuuuuuuude she is so HOT
Person 2: NIIIIIIIIIIIIIIINNNNNNNNNEEEEEEEE
Mr Chittle: You stupid niner
Another word that could be used for this term is Initiation. However niner is a more specific term referring only to grade nine initiations.
This type of initiation is mostly done in school trips that require students to sleep over,(for example; Muskoka Woods camp) and at night around 1:00 to 3:00 AM, grade 11 or 12 students would wake up, and go around "initating" niners in their sleep.
This term is a new type of initation, started in Bishop Allen Catholic High School, in Toronto, Ontario, Canada.