Here's a breakdown:
* Vidkun Quisling was a controversial figure in Norwegian politics. He was a fascist leader who, in 1940, formed a puppet government in Norway under Nazi control.
* During the war, he was a notorious collaborator with the Germans, even going so far as to offer them the use of Norwegian resources and manpower.
* After the war, he was tried for treason and executed in 1945.
Because of his actions, Quisling's name became synonymous with treachery and collaboration with an enemy. The word "quisling" entered the English language in the 1940s to describe anyone who betrays their country by collaborating with an enemy.
Therefore, the word "quisling" is a direct historical reference to Vidkun Quisling's betrayal of Norway during World War II. It has become a widely used term to describe anyone who collaborates with an enemy, regardless of their nationality or political ideology.