Collaboration/Collaborate


col·lab·o·rate

[kuh-lab-uh-reyt] 
verb (used without object), col·lab·o·rat·ed, col·lab·o·rat·ing.
1.
to work, one with another; cooperate, as on a literary work: They collaborated on a novel.
2.
to cooperate, usually willingly, with an enemy nation, especially with an enemy occupying one's country: He collaborated with the Nazis during World War II.