1. A Chicago-based band whose sound is characterized by crunchy metallic riffs and by stop-start rhythms, as well as sometimes cheeky, sometimes emotional lyrics.

Could be (and often is) described as part of the modern pop-punk emo movement, though it has to be noted they are far more rock-oriented and electrically charged than self-admittedly emo bands such as Dashboard Confessional.

Started out fairly indie but has since gained a huge mainstream "pop" audience.

Biggest hits include: Sugar We're Going Down, Dance Dance

Similar bands include: Funeral For A Friend, Panic! at the Disco

2. In the popular TV show The Simpsons, Fallout Boy is superhero Radioactive Man's sidekick.
1. Did you check out Fall Out Boy's new CD?
2. "Radioactive man, look out!" screamed Fallout Boy.
by objective man January 6, 2006
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a band. if you like them fine, if you don't, fine. personally i don't and i've heard some songs, i'm not pulling that opinion out of my ass, like some of these retards. and they're not punk/emo. they are pop. most of the bashing retards wouldn't know emo if it stabbed them in the eye. emo is just another form of punk, not a bunch of pussies in girls' pants slitting they're wrists. i don't know what those tools are. and no need to be homophobic. you can express your hate for something without being a bigot. saying nothing but "gay", "fag", "queer" makes you look like a stupid, homophobic, asshole with no vocabulary, who therefore shouldn't be taken seriously. I've had to thumb down quite a few otherwise valid and funny defintions for being homophobic. not cool.
FanGirl:"OMG! LyKe.....FOB is so0o pUnk RaWk!"
Me:"No, not quite."
Homophobic Asshat:"Fuck Fag Out Boy! Emo faggots and they're gay ass shitty emo music!!"
Me:"Have you even heard 1 Fall Out Boy's of songs?"
Asshat:"Fuck no! I'm not listening to that queer fag crap."
Me:"So, how do you know they suck? Is it because most of their fans are girls? So, just because something is liked by girls it's worthless? Wow, a homophobe AND a misogynst!"
Asshat:"Miso-what? Whatever. Fuck emo fags."
Me: "Define emo."
Asshat:"...It's....those whiny little fags in girls' pants and makeup who.."
Me: "Wrong, tool. Why don't you go learn stuff for yourself instead of accpeting what MTV tells ou it is. I thought you didn't watch MTV?"
by FanGirlHater February 22, 2007
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a fan of Fall Out Boy, that not only wears a Fall Out Boy t-shirt, but has to wear the belt, messenger bag, tie, hat, socks, shoes, everything Fall Out Boy or Clandestine.

They worship Pete The Fall Out Boy. They disregard Andrew Hurley as Jesus, and worship Peter as so.

Lyke, oh my god. Dont you like talk about P3t3 lyke that. He feels for us all. He lyke wrotes such beautiful poems and is So Hawtt. Fall Out Girl is a gang.
by EMILY ARE i May 20, 2006
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the guy that takes the ugly chick so his friend can score with the hot one
my friend met this awesome chick at the club but she had a butt ass ugly friendwith her so i played the fall out boy and kept her busy while he had a night of fun.
by D-Rell The Assassin July 2, 2006
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A fan of Fall Out Boy, she has to have as many posters as possible and all of their merchandise. Fall Out Girls are like a little cult that follow Fall Out Boy. they are true fans of the band, not just fans of Pete Wentz because he is the 'hawt' one. Because he isn't it's so obvious that Andy Hurley is.
I am a Fall Out Girl, I am a true fan of Fall Out Boy
by Fall Out Girl #1 (The Original) September 26, 2007
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having your heart ripped out because you love someone but you don't see a future with them and you can't really break up with them because you don't have a legitimate reason for breaking up with the other person beside you don't feel like being with them anymore.
person 1: dude what's wrong?
person 2: I'm falling out of love with my girl
person 1: that sucks

person 2 : It does, because I don't know what to do about it
by Sam Winchester - 02 August 12, 2018
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Founded in 2000 this band did not start out on top. With the newest album at the moment (from under the cork tree)there sound is different that it has been in the past.
usually Fall out boy's songs have a awesome title like our Lawyer made us change the name of this song so we wouldn't get sued.

by TeArsoNIcE April 4, 2006
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