An energetically stable substance does not react/decompose. The reason for this is there is no lower energy substance it can transform into. For example, water is energetically stable as to decompose into hydrogen and oxygen would require a lot of energy wwhich is not available.

What does it mean to be energetically stable?

You can only say a compound is energetically stable but not a reaction. For a compound, it means that it have a lower energy compared to other related chemical compounds.

What makes something kinetically stable?

Kinetic stability basically occurs when the reactants react really slowly. The slower the reaction occurs, the greater the kinetic stability. If you say, "This reaction is kinetically stable," then that implies that the reaction occurs very slowly.