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