What's the plural form of deviationism? Here's the word you're looking for.
Answer
The noun deviationism can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be deviationism.
However, in more specific contexts, the plural form can also be deviationisms e.g. in reference to various types of deviationisms
or a collection of deviationisms.
Examples
I intend to hold the Commissar for Justice to the CPGB's election promise when they come to lock me up for rightist deviationism.
Follow the revolutionary line of the Third Internationale in the heroic struggle against left deviationism!