collaborationism
col·la·bo·rationism
noun
1.
act of cooperating traitorously with an enemy that is occupying your country
Origin
From collaboration + -ism.
Related words
Word family
Broader terms
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.