When someone fucks up big time or bush leagues big time. One calls it a jerbear. Also when you slur your words not-on-purpose and have the coordination of a drunk Tomasso Martino. A common way to be called a jarebear is to rub your nutless nutsack on your mothers chest then fall down 20 flights of stairs repeatedly in hopes of saving your life that obviously has been in the crapper since you were born. If you are commonly made fun of because you lack the abillity to remember 3 simple digits to your locker combination and your handed a key instead(which you end up losing), and you insist on trying to tie the velcros on your shoes in hopes of fitting it, then you might be a jarebear.
Kid:"Hey you, Jarebear wanna make out"
Accused Jarebear: "Ew no, you must be a cubs fan"
Accused Jarebear: you fwaann flight?, <trips and breaks his glasses"
Accused Jarebear: AHH, I CAN SHEE without my GLASSHES.
A Jarebear: HEY COACH PETERS, LOL i bet i can beat you in bashketball.
C.P: Jerry, did your crap your pants again, i cant take you anywhere, you embarrass yourself.