In the current conflict between Russia and Ukraine, both sides call the opposite one 'Nazis'.
Many politicians or even parties in the West which are not mainstream are also often called Nazis. The most famous example could be Trump, who is definitely a very controversial person, but definitely can't be compared to the Nazis as they existed in Germany between 1933 and 1945.
After 1945, the winners of the war, which represented both the capitalist and communist parts of the world, agreed to some definition of what is a Nazi. I am wondering if that definition is still valid and how exactly it's defined?
What I am asking for is a definition of Nazi by international law or any other internationally accepted authority.