A mentally handicapped individual who is employed in the janitorial profession. Possibly as part of a societal integration program, or because it's funny as hell to watch...
Someone who is accepted at a college for the spring semester rather than the fall semester. Generally, they are inferior to the fall admits in intelligence, though there are few exceptions.
"Yo Matt, don't talk to that kid in the corner, he's one of those jantards."
When you fail at something in life (eg. failing an exam or not getting a job), go home and spend an hour just standing in the shower, propping yourself up against the wall with your eyes on your feet.
Caleb knew the only thing to do after he didnt get prefect was take a failure shower.