1. In the eyes the very newest members of any band's fanbase: any band after any album they release; that same band once they work hard and earn the respect of a large-scale audience by giving the world music various types of people can enjoy. "HOW DARE THEY BE SUCCESSFUL? THE SELFISHNESS OF IT ALL! I WANT THEM TO BE BANKRUPT AND MISERABLE AND COMPLETELY UNKNOWN, THAT WAY I CAN RECOMMEND THEM TO PEOPLE WHO TELL ME 'Nah, I'll pass.' !"

2. A nonsensical term slung about by high school students to describe bands they have no true interest in (only their t-shirts) after the band released an album said fans were not even born early enough to experience. see also: False aging/wisdom/experience in a teenaged body

3. A band that truly is only in the music industry for the money see also: Metallica/Slayer/Tool/Avenged Sevenfold

4. A fan who is truly only in a fanbase for the sheer trendiness.
STEVE: "My kid brother's really into Metallica."
GREG: "Really? That sounds rich! Hey Alex, what did you think of Death Magnetic?"
ALEX: "Oh my fucking God, don't even get me started on that bunch of sell out nerds with a clear opera fetish! Trust me man, I was at their very first show back in nineteen-eighty-whatever and take my word for it: they haven't made a good album since Ride the Lightning, which was WAY better on vinyl, by the way!"
GREG: "Um, Alex, you were born in 1996. Records are obsolete and no one even makes record players anymore."
ALEX: "What's you point, faggot?"
by Zalgo the Destroyer October 23, 2010
Get the Sell Out mug.
Not just someone who sells out their music.....also can be used when friends backstab you, or ignore their own self imposed belief system of morals and ethics and do something that they never ever said they would.
'But he said wouldn't'
'Yeah well he's a fucking sellout'
by Johhny Rogers December 7, 2003
Get the Sell Out mug.
when a person (most oftenly a musical artist) comprimises their beliefs to further their success and make loads of money. However, this is not to be confused with when a band that you liked, that was perviously not popular, becomes popular.
britney spears sold out when she decided to take off all of her clothes in order to see more albums.
by Rachel December 11, 2003
Get the sell-out mug.
Compromising your integrity, usually for money. Its that simple. This word is mostly used to describe bands that go mainstream.
Green Day aren't sellouts because despite their recent popularity, they never changed their sound. They were just never very good...
by Crak March 26, 2005
Get the Sell Out mug.
when a band or something abandons what theyre viewed as and change to a more higher paid stream where they satisfy posers and mainstream jockies and concert invaders who only know 2 or 3 songs claiming to be huge fans
Person 1: Ugh Kings of Leon are such sell outs!
Person 2: Right!, you win a Grammy and get on the radio and then continue with horrible music.

Guy: Hey have you guys heard "Tighten Up" on the radio? I Love The Black Keys, i bet they'll win that grammy.

Person 1 & 2: NOOOOOOO! Not The Black Keys!
by RealMothaFucka December 19, 2010
Get the Sell Out mug.
I've seen a lot of definitions so far that arent really correct. But quit a few of them are right on point. A sell out is a person or person(s) that change to become more successful . It can also mean to conform to suit someone else.

An unpoppular band that someone likes may call that band a sell out when everyone starts liking them. Often it is these people who sold out when they became popular.

People also concider people such as bands, actors, actresses, and other icons ETC sellouts when they become very successful and popular. It seems the only way people can avoid selling out is to not become successful and unloved by people.

People who call others sellouts never think that these people who are accused of selling out to make money came it said business' to become successful in the first place.

The people who often concider people to be sellouts are often jealous assholes who want what they have.

See jealousy
The black eyes peas were concidered sell outs after changing one of their songs from "Lets Get Retarted" to "Lets get it Started" to fit the wants of their record lable and whinney bitches who felt offended.
by Zach cowan October 2, 2006
Get the Sell Out mug.
A band has “sold out” when their fans no longer get feel like part of an elite clique. This generally happens when a band attracts interest from a major label, who provides them with a higher recording budget, which results in just enough polish to make the band acceptable to a slightly wider audience; unfortunately, the better production generally reveals the band’s basic lack of musical talent, which hipsters could previously not see because it was hidden behind a blurry cloud of “lo-fi.”. What hipsters once assumed were “fractured pop songs” are revealed to simply be “bad pop songs,” and the hipsters aren’t smart enough to figure out why their favorite band suddenly seems to suck way more than before, so they blame it on “commercial production” and this mysterious and ephemeral force of “selling out.”

Dr. David Thorpe
Hipster: Selling out to the corporate machine! Ahhhhhhhhh.
by M-Sauce July 28, 2006
Get the selling out mug.