Euthyphro ends up agreeing that the definitions of piety he has proposed are inadequate. How would you explain what was wrong with them?

Euthyphro first defines "piety" as what he was doing at that time, that is prosecuting Euthyphro's father for manslaughter. His definition of piety was inadequate as Socrates states that it is only an instance or example of piety and not the proper definition of piety itself. It is not able to provide a fundamental characteristic that makes pious things pious.