What Does Lawful Good Mean

What is the difference between lawful good and neutral good?

Lawful characters believe society functions most effectively with rules and order, while Chaotic characters believe that order restricts individual freedoms. Neutral characters do not feel compelled to follow every rule and societal belief, nor do they feel the need to ignore or rebel against societal order.

Can lawful good be evil?

Would a Lawful Good character serve the greater good by being Evil, and could they still be considered Lawful Good, if they were only Evil because the greater good demanded that they be so? In my opinion, no. Good and Evil is partly about what lines you will not cross.