Führer
From Memory Alpha, the free Star Trek reference
Führer (or Fuehrer) is a word from the German language which means leader. It was the title which Adolf Hitler took in 1934 when he took absolute power in Germany on Earth, and it referred to the offices of President and Chancellor rolled together into a single office led by a single individual.
In a holoprogram set in 1944 France, a Nazi officer told Turanj that Karr had never embraced the Fuhrer or his vision and they were therefore right to disobey his orders. (VOY: "The Killing Game, Part II")
John Gill, the respected Federation historian, also took this title when he created the Nazi state on Ekos in the mid-23rd century. (TOS: "Patterns of Force")
