What exactly does "nonspecific" mean in an upper endoscopy?

Define "nonspecific": "Nonspecific" often applies to a pathologic finding that is not definitive or distinguishing alone to make a diagnosis. For example, gastritis may be considered nonspecific, unless there are features present that allow one to characterize the mucosal changes seen as peptic, atrophic, caustic, etc.

Endoscopy: All that "nonspecific" means is that there were not findings that demonstrated a specific diagnosis. This does not mean that there was nothing wrong, it just means that there was nothing found to point in a definite direction. You may need more testing or a trial of medicine. Hope this helps.