These are the girls who aren't real fans. They're incredibly annoying, have never looked at a dictionary, and tend to abuse the caps lock key. Mainly in the tween age group, it is very easy to tell when one is a Jonas Fangirl.
They are obsessed with the Jonas Brothers looks, and get mad when someone dates a Jonas Brother (other than themselves.)
Occasionally, they even yell at other fangirls who think a certain Jonas is theirs, which has led to many arguments. If someone says their opinion and happen to not like the Jonas Brothers in any way, the fangirls have a spaz attack and attempt to insult the other person with unintelligent remarks.
Not to be mistaken for a NJF (normal Jonas fan.)
Guy: I don't like the Jonas Brothers music, they suck at singing.
NJF: Oh. I like their singing, but that's your opinion.
Jonas Fangirl: OMGGG THEY R SOOO GREAT U R JUST JELOUS CUZ I BET U CANT SINGG ND THEY R PERFCT SOOOOOOOOOOO HAWTTT AND LYKE THEY HAV PURTY RINGS SO THEY R BETTER THEN U.U DONT NO GUD MUSIC SO F*** OFF YOU GAY F**!!!!!1!!11ONE!