Anarchism is a political philosophy and movement that rejects all involuntary, coercive forms of hierarchy.
It is usually described alongside libertarian Marxism as the libertarian wing (libertarian socialism) of the socialist movement and as having a historical association with anti-capitalism and socialism.
With the rise of organised hierarchical bodies, scepticism toward authority also rose, but it was not until the 19th century that a self-conscious political movement emerged.
During the latter half of the 19th and the first decades of the 20th century, the anarchist movement flourished in most parts of the world and had a significant role in workers' struggles for emancipation.
Revolutionary tactics aim to bring down authority and state, having taken a violent turn in the past.
Anarchist thought, criticism and praxis have played a part in diverse areas of human society.
The etymological origin of anarchism is from the Ancient Greek anarkhia, meaning "without a ruler", composed of the prefix an- (i.e. "without") and the word arkhos (i.e. "leader" or "ruler").
Since the 1890s and beginning in France, libertarianism has often been used as a synonym for anarchism and its use as a synonym is still common outside the United States.
While the term libertarian has been largely synonymous with anarchism, its meaning has more recently diluted with wider adoption from ideologically disparate groups, including both the New Left and libertarian Marxists (who do not associate with authoritarian socialists or a vanguard party) as well as extreme liberals (primarily concerned with civil liberties).
Daniel Guérin wrote: [A]narchism is really a synonym for socialism.
The anarchist is primarily a socialist whose aim is to abolish the exploitation of man by man.
While opposition to the state is central to anarchist thought, defining anarchism is not an easy task as there is a lot of discussion among scholars and anarchists on the matter and various currents perceive anarchism slightly differently.
Hence, it might be true to say that anarchism is a cluster of political philosophies opposing authority and hierarchical organisation (including capitalism, nationalism, the state and all associated institutions) in the conduct of all human relations in favour of a society based on decentralisation, freedom and voluntary association.
However, this definition has the same shortcomings as the definition based on anti-authoritarianism (which is an a posteriori conclusion), anti-statism (anarchism is much more than that) and etymology (which is simply a negation of a ruler).
Nonetheless, major elements of the definition of anarchism include the will for a non-coercive society, the rejection of the state apparatus, the belief that human nature allows humans to exist in or progress toward such a non-coercive society and a suggestion on how to act to pursue the ideal of anarchy.
It cannot be reduced to socialism, and is best seen as a separate and distinctive doctrine".
According to Jeremy Jennings, "[i]t is hard not to conclude that these ideas", referring to anarcho-capitalism, "are described as anarchist only on the basis of a misunderstanding of what anarchism is".
[...] In a sense, anarchists always remain liberals and socialists, and whenever they reject what is good in either they betray anarchism itself.
Brian Morriss argues that it is "conceptually and historically misleading" to "create a dichotomy between socialism and anarchism".
It was after the creation of towns and cities that institutions of authority were established and anarchistic ideas espoused as a reaction.