What was an untermenchen?

The Untermenchen were the people seen by Hitler as "sub-human" as "Unter Männern" literally means, "below men", such as the Jews. In addition to the Jewish people, this also applied to homosexuals, persons of African descent, atheists, political "criminals", communists, trade workers, advocates of democracy, etc. (basically anyone who was opposed to the Third Reich for whatever reason, or opposed it's ideals).