anti-fascism: A political movement in opposition to fascist ideologies, groups and individuals. Antifa is a highly decentralized anti-fascist action and left-wing political movement in the U.S. comprising of autonomous groups and individuals that use of both nonviolent and violent direct action rather than pursuing policy reform.
CONTEXT & HISTORY:
Anti-facism is a political movement in opposition to fascist ideologies, groups and individuals. It began in a few European countries in the 1920s and eventually spread around the world. (wikipedia)
Antifa is an anti-fascist action and left-wing political movement in the United States comprising an array of autonomous groups and individuals that aim to achieve their objectives through the use of both nonviolent and violent direct action rather than through policy reform. A highly decentralized movement, antifa political activists are anti-racists who engage in protest tactics, seeking to combat fascists and racists such as neo-Nazis, white supremacists, and other far-right extremists. This may involve digital activism, harassment, physical violence, and property damage against those whom they identify as belonging to the far right. Much of antifa’s activism is nonviolent, involving poster and flyer campaigns, delivering speeches, marching in protest, and community organizing on behalf of anti-racist and anti-white nationalist causes. (wikipedia)
The broadest answer to this is that antifascism is any activity that is intended to oppose and/or disrupt fascist organizing. This can range from the “everyday antifascist” who participates in call-in campaigns, sends in tips and helps build an antifascist culture that is resistant to fascism, or militant antifascists like Rose City Antifa who work to ensure that there are consequences for fascists who spread their hate and violence in our city. (Rose City Antifa)
A Brief History of Anti-facism from Smithsonian Magazine (7-minute read)