Wiktionary
a. Referring to someone who is opposed to the existing system (the establishment).
Wikipedia
An anti-establishment view or belief is one which stands in opposition to the conventional social, political, and economic principles of a society. The term was first used in the modern sense in 1958, by the British magazine New Statesman to refer to its political and social agenda. The term can be distinguished from counterculture, a word normally used to describe artistic rather than political movements that run against the prevailing taste and values of the time. Although the term has retained its original meaning in British English and continues to be applied to various individuals and groups, in American English the term is used more specifically to describe certain social and political movements that occurred during the 1950s and 1960s.
Anti-Establishment was a UK Punk band, formed in 1978. They went through a number of line ups before settling on the lineup that would record the majority of their material: Gavin Gritton on vocals, Nick Freeston on drums, Haggis on lead guitar, and Kevin Read on bass. The first gig was in 1979. The band initially only went on to play around 25 shows but, as it says in the liner notes to the compilation of all of their work compiled by legendary label Captain Oi! Records in 1997, 'the name Anti-Establishment is still held in high esteem amongst the Oi!/Punk Fraternity'.
The first single was '1980's/Mechanical Man', produced by The Damned drummer Rat Scabies and released in March 1980 under the Charnel House label.
The second single was 'Future Girl/No Trust' produced by Rat Scabies, released on Glass Records. It was promoted with a tour supporting The Exploited.
The third and final single was a double A side 'Anti-men' and 'Misunderstood', again produced by Rat Scabies. A line up change saw Gary Dawson on Guitar after Haggis left to spend time building up his own garage business.
The band reformed in 2013 and played the Rebellion Punk Festival.
Usage examples of "anti-establishment".
There are kids that get their anti-establishment milkman's overalls in the Marsha Jordan Shop with their own charge card.
Ever since thumbprint-secured debit cards had become the principal medium of exchange, the shrunken remnant of the cash economy belonged to small-time tax evaders, anti-establishment iconoclasts, debtors on the run, and other assorted cranks and petty criminals.