The medical term idiopathic comes from Greek roots: idios, or "one's own," and pathos, "suffering" or "disease." The literal meaning is something like "a disease of its own," or an illness that isn't connected to any particular cause. This is often the diagnosis doctors end up with after ruling out a lot of known conditions or diseases, and it's an official-sounding way for a medical professional to say "I don't know why you're sick."