Sell out

"Selling out" is a common idiomatic pejorative expression for the compromising of a person's integrity, morality, , or principles in exchange for personal gain, such as money. In terms of music or art, selling out is associated with attempts to tailor material to a mainstream or commercial audience; for example, a musician who alters his material to encompass a wider audience, and in turn generates greater revenue, may be labeled by fans who pre-date the change as a "sellout."

A sellout also refers to someone who gives up, or disregards, hence the term 'sells' - someone or something - for some other thing or person. The term could also be used as 'sold out' depending on the context.

In political movements a "sellout" is a person or group claiming to adhere to one ideology, only to follow these claims up with actions contradicting them, such as a revolutionary group claiming to fight for a particular cause, but failing to continue this upon obtaining power.

An example of political "selling out" is a political party who has formed a coalition with another party it had historically opposed, such as the Liberal Democrats' leader Nick Clegg's coalition with the Conservative Party after the 2010 general election in the United Kingdom.

There are two distinct forms of "selling out" in terms of music. First, there is the use of term "sell out" to refer to those who sign for major labels or to those who licence their music to companies for use in advertising that contradicts their apparent values. Secondly, the expression can refer to those who sacrifice their musical integrity through a change in their musical sound, sometimes due to pressure from major labels or in order to gain profit by making their music more appealing to a mainstream audience.

Since the time of big band radio shows there has been an established relationship between musicians and commercialisation. It was not until the punk subculture in the 1970s that the notion that musicians should be completely independent of commercial influences began to increase in popularity. This partly manifested itself in the reluctance of bands to sign for major labels, as this would include taking part in activities that were seen as crass and overly commercial. This continued into the 1980s, when bands were scorned by fanzines for signing with major labels as the mainstream success this would bring was symptomatic of the general decay in culture. However, after a number of bands maintained the quality of their records after signing for a major label, by the end of the 1980s the focus on "selling out" shifted to advertising.

...
Wikipedia