One who deviates from accepted beliefs or policies, especially from a prescribed form of Communism.
2007 June 13, William Grimes, “Surviving Under Mao: A Slacker’s Guide”, in New York Times[1]:
Theirs was the confession, and Mr. Kang turned them out by the dozen throughout his life, expiating one supposed crime after another by denouncing himself as a reactionary element, a deviationist and whatever else was on the political menu that day.