Here's a breakdown:
* Shur is a prefix used to denote something as being "without" or "lacking".
* Tugal is a word for "dragon" in the language of the Riders, the ancient people who rode dragons in the *Inheritance Cycle*.
Therefore, "Shurtugal" literally means "without a dragon rider" or "a dragon that has no rider".
It's a significant term in the series, highlighting the vulnerability and isolation of a dragon without its bonded rider.