How does evil disprove God? What do you mean by evil?

I'm not asking for examples of evil, but a definition of evil.

Evil is a lack in Good. Evil doesn't exist on its own, but only as a privation in Good.

Evil is like rust in a car. If you take all the rust out of the car you'll have a better car. But if you take all the car out of the rust, you'll have nothing.

Since evil is a lack in Good, there can be no objective evil unless there is objective good. And there can be no objective good unless there is a standard of good outside of ourselves-beyond mere human opinion. That standard is God's very nature.

In other words, the shadows (evil) prove the sunshine (good). Just like there can be sunshine without shadows but no shadows without sunshine, so there can be good without evil but no evil without good. And there can't be objective good without God.

So in order to say that evil disproves God, you would have to borrow from God in order make the argument! You are borrowing a standard of good, which only exists if God exists.

Evil may prove there is a devil out there, but it doesn't disprove God.