That which is mysterious, by being unknown or puzzling, excites curiosity or awe: a mysterious disease. inscrutable applies to that which is impenetrable, so enigmatic that one cannot interpret it: an inscrutable smile. "Mysterious" refers to something that is difficult or impossible to understand, explain, or identify.

Understanding the Context

It often pertains to circumstances, situations, or objects that are characterized by secrecy, obscurity, or are enigmatic in nature, which can arouse curiosity or fascination.