To my simple, secular, mind that first definition is the best one.What is the nature of evil in both a religious and secular sense?
Although I'd phrase it differently. What enhances the overall human situation is good. What degrades it is bad. Evil is the more extreme end of the bad part of the spectrum.To me, one of the more interesting definitions of evil that was advanced during the semester was that evil consisted in "the denial life" while good consisted in "the affirmation of life". I thought the definition had some problems with it, but that it was a good start. Another definition was that evil could be defined as "anything offensive to God". And, of course, there was the definition of evil as just another name for "bad". There are lots of ways to define evil, both religious and secular, but some ways seem more useful than others.
Tsunamis are very evil. But as an "Act of God", having no human agency involved, we don't usually talk about them that way. Because people usually mean human behavior and choices, that is, morality. And that's when things get messy, subjective and relative. Because humans have such wildly different opinions about what improvements and damage mean, under many circumstances. How to do the moral calculations of the cost/benefit analysis of available choices. And we humans are pretty stupid really, with weak powers of perception and reasoning. We're highly prone to delusion and mistakes that we should have known better than to make. And then we tend to double down on the mistake, convincing ourselves that our choice was justified!
I have very little use or patience with religious meanings for evil. They're virtually always attempts at justifying behavior on the basis of what some human insists that God really meant by some Scripture. When, obviously, God is the being Who created us stupid, ignorant, weak, and prone to delusion.
To me, the True Problem of Evil is "Why did God make us like this?" I understand why we Evolved this way. Natural selection reproduces genes that give survivability. That's often ruthlessness, much less often empathy and cooperation. As a result, humans tend towards immoral behavior unless they're taught better by the humans around them. God, if He exists, doesn't help.
Tom