The title of a Fall Out Boy song from the CD, Take This To Your Grave.

Led by a guy with down syndrome who tries to sing and pretty much just mumbles to cover up his emo lyrics. The only people who understand this retard are other retards known as emos, who are all worthless pieces of shit and don't deserve their lives.

The mysterious occurence of when a fan of a band starts to suddenly hate said band as soon as they become popular, appear on MTV, and are heard on the radio. Often, a fall out fan will insist that the band was ruined by mtv, when, in reality, the band has not changed at all except for their popularity status. Usually is in response to all the new teeny bopper fans. Named so for the band Fall Out Boy, which has many fall out fans.

1) Bassist for the pop (you are NOT punk, get over it) band Fall Out Boy, who nevertheless recieves more attention, fans (mostly little girls), camera time (in their axe-commercial music videos), and tabloid space then all other members of the band. Has his own clothing line, record label, and Ashley Simpson. Feels an unexplainable need to post pictures of his dick on the internet.
2) The root of all evil. The reason for bands with a lot of talent and potential like Panic! at the Disco reaching Top 40 radio to early (they should work for their fame, not be mass-produced in their first album.) The reason for millions of 13-year-old girls across the globe thinking they're punk because they have a picture of him in their locker. Most likely the reason Ashley Simpson is pregnant (supposedly). Pete Wentz can also be blamed for global warming, inflation, and the Minnesota bridge collapse.

A 'fall out girl' is a typical fangirl of the band Fall Out Boy. They squee whenever they listen to Sugar We're Going Down, and basically talk like this:
"OHMYGAWD! PETE WENTZ IS LYKE sooooooo HAWTT! *SQUEE!* Lykee I LURVE THARNKS FR THA MEMOREES! *SQUEE!*"
Basically, they love the band for Pete, and only Pete. (and maybe his dick).

A Fall out whore is a usually ditsy girl with no taste in music who listens to Fallout Boy constantly and insists on how great they are 24/7.

most people understand that high school relationships do not go anywhere, so when someone thinks they love someone in school, sensible people rational that you've only fallen in "like" with that person, a lesser degree of love.