Fascism is well defined, it is capitalism in decay, it is a desperate lashing out of the parasite class when they become incapable of forestalling the TRPF. Fascism is simply capitalism with the mask off. It is only "not a very well defined term" within the capitalist superstructure because they don't want people oppose capitalism, so the definition deliberately muddied. There are many things that are not poorly understood, but must be made to be poorly understood.