Collaborationism is cooperation with the enemy against one's country in wartime.

Stanley Hoffmann subdivided collaboration onto

According to him, collaborationism can be subdivided onto

the former is a deliberate service to an enemy, whereas the latter is a deliberate advocacy of co-operation with the foreign force which is seen as a champion of some desirable domestic transformations. In contrast, Bertram Gordon used the terms "collaborator" and "collaborationist" for non-ideological and ideological collaborations, respectively.