What's the plural form of halfness? Here's the word you're looking for.
Answer
The noun halfness can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be halfness.
However, in more specific contexts, the plural form can also be halfnesses e.g. in reference to various types of halfnesses
or a collection of halfnesses.
Examples
As soon as there is any departure from simplicity, and attempt at halfness, or good for me that is not good for him, my neighbor feels the wrong.