treholt, a word Norwegians are not very proud of having given to the world: it derives from Arne Treholt, a notorious
Norwegian traitor who collaborated with the communists during the Cold War, and who was convicted of spying for the
KGB in 1985 and sentenced to 20 years in
prison. He established his name as a synonym for "traitor". It is, arguably, the worst and most grave insult a Norwegian can throw at another.