How do you use swarthiness?

"Swarthiness" is not a commonly used word in English. It might be a made-up word or a very specific term within a particular field.

If you could provide more context, I might be able to help you understand what it means and how to use it.

For example:

* Where did you encounter the word "swarthiness"? (a book, a conversation, etc.)

* What is the topic or subject matter?

* What were you hoping to achieve by using "swarthiness"?

Please provide more information so I can assist you better.