The term varies usually indicates a variety of possibilities depending on the context of the usage.
For example, "Race = Varies" usually indicates the race of the subject varies within a range based on the creature type. So, if the type were humanoid, but the subject were part of the Horde, the race would be a humanoid race among the common Horde races (blood elf, Forsaken, orc, tauren, or troll). Also, if the subject were of a particular class, like a priest, the race would also be restricted by those races available to a priest (assuming Horde; blood elf, Forsaken, or troll).