The sleep-deprived, zombie-like disease of a high-school junior who has overdosed on AP or honors classes and extracurriculars.
A person with junioritis exhibits characteristic tendencies such as caffeine dependence, poor posture, a bleak social life, and basic hatred for anyone without homework. Used as a noun or occasionally as an expletive, if said with enthusiasm.

Your third year of high school. Junior year means you are finally an upperclassman, after two years of crap at the sophomore and freshman ranks. However, as a junior, you still aren't the top dogs in the school, and still have another year to take orders from older douchebags. Junior year marks the beginning of the second half of your high school career...Good Luck.

The condition of being so fed up with Junior year work (eg. AP/Honors courses work, SATs, IBs, SAT IIs, ACTs) that a person experiences mental breakdowns, frustration, and bouts of "DGAF"-ing. The state of being unable to concentrate shortly follows.

The condition of being so unable to focus, that Junior updates definitions of "Junioritis" on Urban Dictionary, rather than do their work.

The "living dead" who overload on AP and honors classes because the only thing they think about is getting into the best college they could imagine. It is a known fact that all are dependant on caffeine.

A smart kid that would go and be rich

Someone of a more junior nature. Opposite of seniority.

later know as Senioritis. Usually worse since senioritis is almost over but knowing you have another year but seniors have graduation in sight. Effects 99 percent of juniors taking difficult classes and extra curricular activities while trying to keep their grades up for scholarships and acceptence for college. They have experienced the life of a highschool teen, resulting in, now wanting to live the college life.

Only known cure: graduation, dropping out