quisling
Definitions
A traitor who collaborates with an enemy force occupying their country.
A person who betrays their own country by aiding an invader.
Examples
The historical records revealed that the local official was a secret quisling who provided intelligence to the invading forces.
He was branded a quisling by his former allies after he abandoned the resistance to join the enemy's puppet government.
Synonyms
traitor turncoat collaborator renegade defector betrayer double agent