See the article on National Socialism regarding the ideology

Nazi is derogatory term for National Socialist.

The word was originally an abbreviation of the German pronunciation of "Nationalsozialist" (in part from the earlier German "sozi", popular abbreviation of "socialist"), from the "Nationalsozialistische Deutsche Arbeiterpartei" or the National Socialist German Workers' Party. The earlier derogatory nickname "Nazi" or "Naczi" has been argued to "Nazi" being used by opponents.[1]

Related words include Nazism and Neo-Nazism.

Usage

The word was and is used almost exclusively by opponents.

The NSDAP briefly adopted the word, in attempt to give it a more positive sense, but soon gave up this effort and generally avoided it while in power.[1] A rare example of its usage is a 1931 work by Joseph Goebbels titled The Nazi-Sozi: Questions and Answers for National Socialists.

George Lincoln Rockwell is a rare example of a supporter using the word, such as in the American Nazi Party, possibly for its shock value and/or as irony

In the Soviet Union, the terms National Socialist and Nazi have been stated to have been forbidden after 1932, presumably to avoid any taint to the word "socialist". Soviet literature instead referred to fascists.[1]

As an example of popular political correctness and political bias, compare the usage of the term "Soviet Union" with "Commie Russia", cheap name calling.

Despite this, using "Nazi" or "Nazism" instead of "National Socialist" or "National Socialism" is extremely common. For example, Wikipedia routinely uses "Nazi", despite not using "Commie".

Today, the term and its derivatives are widely used as ad hominem and guilt by association against a wide variety of politically incorrect individuals and organizations, despite not being National Socialist.

Nazi at Online Etymology Dictionary