If you know what fascism is then you are nearly alone in the world. Read over the Wikipedia definition of fascism and you'll find it starts with a comparison to "nailing jelly to the wall".
Trump isn't literally Mussolini, and he isn't even personally a fascist, just a political opportunist with no principles- but the movement he is part of literally fits the entire first paragraph of the Wikipedia article to a T.
The most solid explanation is in this part: https://en.wikipedia.org/wiki/Fascism#Fascist_as_a_pejorativ...