(the definetion should probably be made clear, before or after use, since there is the literal kind of oily. ick)
This is an old term, from somewhere such as Leave It To Beaver.
"damn that bitch oily"
"What can i say, i'm oily, I rise above the rest"
That was the oiliest math test I've ever taken. All of the questions were about strippers, and they all had the same name as the professor.
Our Biology teacher makes us draw random pictures on the back of our tests while he shoots us with rubber bands. He is insanely oily.