•UK law a barrister or advocate (SCT) appointed by letters patent to be one of
Her Majesty's Counsel learned in the law during the reign of a female monarch.
•Also: King's Counsel (KC) during the reign of a male monarch. [WIKI]
•a traitor who serves as the puppet of an enemy occupying his or her territory.
(=after Vidkun Quisling (1887-1945), head of Norway's government during the Nazi occupation (1940-1945).)
[AHD]