What is a syndrigast?

From the text:

“The composition of the human species is infinitely more diverse than most humans suspect,” she began. “The real taxonomy of Homo sapiens is a secret known to only a few, of whom you will now be one. At base, it is a simple dichotomy: there are the coerlfolc, the teeming mass of common people who make up humanity’s great bulk, and there is the hidden branch — the crypto-sapiens, if you will — who are called syndrigast, or “peculiar spirit” in the venerable language of my ancestors. As you have no doubt surmised, we here are of the latter type.”