1. the practice of collaborating with an occupying enemy force; treacherous cooperation with invaders
Usage: historical; often capitalized

Examples

• The government accused several officials of quislingism during the occupation.
• His quislingism made him a pariah among his former countrymen.
• The historian studied various forms of quislingism across occupied Europe.
• Many viewed any cooperation with the invaders as quislingism.
• The trial focused on charges of quislingism and treason.
• Quislingism became synonymous with the worst form of betrayal.