What's the plural form of Quislingism? Here's the word you're looking for.
Answer
The noun Quislingism can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be Quislingism.
However, in more specific contexts, the plural form can also be Quislingisms e.g. in reference to various types of Quislingisms
or a collection of Quislingisms.