Hitler

wiktionary

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The surname Hitler is a variation of Hiedler, a surname applied to those who resided near a Hiedl(“subterranean river”) (Bavarian dialect). [1] [2] Earlier theories [3] derived the surname from Hüttler (also spelled Huettler), either meaning "one who lives in a hut", from Hütte(“hut”), or from hüten(“guard, look after”).

etymonline

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Hitler

used figuratively for "a dictator" from 1934.