Wow, that’s a crazy looking word! I am sure I had never heard it before I read “His Last Bow”, one of The Greatest Adventures of Sherlock Holmes. But, based on the context, I don’t think the word means crazy. For this word, we have to start at the base noun and the build on it so we fully understand it.

Stertor – an abnormal snoring sound accompanying breathing

Stertorous – characterized by starter or heavy snoring; breathing in this manner

Usage: “The German lay upon the sofa sleeping stertorously.”