Vidkun Quisling (1887-1945) served as an army officer in Norway when he founded Norway's fascist party in 1933. Then, in December 1939, Quisling met with Adolf Hitler, and Quisling urged Hitler to occupy Norway. Hitler then invaded in April 1940.
In reward, Quisling became the figurehead of Germany's puppet government in Norway.
Quickly, even before the end of 1940, the term "quisling" in English became known to mean any traitor, and it was used by Winston Churchill, George Orwell, and H. G. Wells.
Quisling was executed for treason in 1945, shortly after Norway was liberated from Nazi control.