collaborationism
noun
col·lab·o·ra·tion·ism kə-ˌla-bə-ˈrā-shə-ˌni-zəm 
: the advocacy or practice of collaboration with an enemy
collaborationist
kə-ˌla-bə-ˈrā-sh(ə-)nist
adjective or noun 
Example Sentences
Recent Examples on the Web The message that united two-thirds of French voters behind Macron was to oppose the National Front, a narrative so powerful that the sitting French ambassador to Washington got on the radio to compare a Le Pen victory to Vichy-era collaborationism. 
Matt Peterson, The Atlantic, 13 May 2017
Matt Peterson, The Atlantic, 13 May 2017 Word History
First Known Use
1923, in the meaning defined above
collaborationists
noun
as in collaborators
Synonyms & Similar Words
Relevance
- collaborators
- informers
- accomplices
- informants
- confederates
- abettors
- abetters
- traitors
- comrades
- cohorts
- partners
- henchmen
- conspirators
- accessories
- accessaries
- evidences
- cronies
- gangsters
- racketeers
- plotters
- mobsters
- companions
- state's evidences