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