The very common combination of the laziness a student exhibits on their senior year of high school, otherwise known as senioritis, and procrastination. Thus, senioritis + procrastination = proitis.
1: Dude, have you done your enlgish paper yet?
2: Naw, i will turn it in next class
1: It was due 3 weeks ago! You definately have proitis
2: Can't help it...