Antifa can be described as a transnational insurgency movement that endeavors, often with extreme violence, to subvert liberal democracy, with the aim of replacing global capitalism with communism. Antifa's stated long-term objective, both in America and abroad, is to establish a communist world order. In the United States, Antifa's immediate aim is to bring about the demise of the Trump administration."
[zerohedge.com]
I would say that antifa is a fascist organization that tries to bring down true democracy. They tried to be clever by calling themselves anti-fascist but the only people they fool are the majority who can't be bothered looking more deeply into political movements. The more astute minority, however, sees antifa as the gang of fascist thugs that they really are.