Just back from screening a 1929 silent film (Douglas Fairbanks in "The iron mask") which included the following intertitle:

"You dolt! You bungler! You marplot! … "

I hadn't heard the word "marplot" before -- it means exactly what it says: "A person who spoils a plot or hinders the success of any undertaking." [18th century English -- SOED]

I assume it was the English translation of a similar French word (in Dumas's novel), but was it in use in 1929?