Comes quite naturally if you're familiar with German word construction.

That said, it doesn't seem to have emerged into widespread use until well after the 1950s, so would have been a peculiar choice for a 19th century author:

<https://books.google.com/ngrams/graph?content=creditworthine...>

Ok. Why? You could also use credit but creditworthiness works better for both contexts.

I figure you’re just being snarky but still.