great Scott

Uncertain or disputed. May come from either the Scottish novelist Walter Scott, so called in some poems, or Gen. Winfield Scott of the American Civil War, who weighed about 300 pounds and was referred to by his troops as "Great Scott". Alternately, perhaps a corruption of German grüß Gott! (“Good day!, Hello!”, literally “May God greet (thee)!”), or a euphemism for great Satan or good God.