Synonyms of the word

collaborationist

• n. One who collaborates, a collaborator.

collaborator

• n. A person who works with others towards a common goal.
• n. A person who cooperates traitorously with an enemy.

quisling

• n. (pejorative) A traitor who collaborates with the enemy.

traitor

• n. One who violates his allegiance and betrays his/her country; one guilty of treason; one who, in breach…
• n. Hence, one who betrays any confidence or trust.
• v. To act the traitor toward; to betray; to deceive.
• adj. traitorous.

treasonist

• n. One who commits treason.