I believe that anything that brings one joy is an act of goodness, therefore, evil would be something that destroys joy.
It is easily seen that goodness is winning the war. Thousands of years ago we fed people to lions for sport and entertainment. Several hundred years ago we burned people at the stake for being witches, we show progress and goodness is winning the battle, and will always win, because it is more powerful than evil. I believe a more defined definition will allow us to focus on evil and continue to diminish its power.
The moral majority will come together to state that an action is evil, but this is not enough to determine a true act of evil. I believe that an evil act is self-destructive and is something that an individual will do on purpose knowing that it will destroy the joy they have for living. Accidents can be forgiven.. so the individual must understand, before they carry out the action or thought, that the action will destroy their personal joy. Then it can be declared an act of evil. Many people enjoy the concept of being evil, this destroys the nature of what evil would represent. There would be no joy in being evil.. only misery.
I have also contemplated that evil is something that keeps one from attaining joy. Easily summed up.. evil is that which keeps the ego from becoming the super-ego. An absence of light. We will never be able to overcome this because we understand there is no possibility of achieving perfection, therefore, we will always possess a belief that we can be better. We will always be able to visualize a superior form than the one we currently inhabit.
A third issue concerning the nature of evil is an action I have dubbed "the adversary". This action betrays what is the known standard when seeking to achieve happiness and joy. It is akin to murdering a relative for the inheritance. An individual will gain joy from committing the murder for the inheritance, but it is taught that such an act should never give the individual joy. There are those, however, who do not succumb to the feelings of guilt. They do not fold beneath the realization of what they have done. I do not necessarily call such an action evil, but a grotesqueness. The action still brings joy into ones life, but it overshadows certain emotions that are necessary to create a profound joy that is incomparable to someone who commits a grotesque act in order to achieve happiness. Grotesque actions limit the feeling of ecstatic bliss.
Most people who seek evil are only carrying out actions that they were taught were evil. Those that use a spiritual thought process to comprehend life are aware that their diverse belief system is often called evil by organized religion. It is clear that such pathways are not evil. Those individuals who worship evil are seeking attention. That is why I believe the root of all evil is the need for attention. To fulfill this need for attention people will commit horrific acts.
There are three things that I think exemplify evil:
1. Hatred - Of oneself and of the universe for forcing one to exist, it is a force of rejection
2. Oppression and prejudice - The refusal to listen to others and the want to stop others from expressing their opinion.. leaving only your personal viewpoints to be expressed
3. Refusal to adapt - An evil person will assume they are perfect and expect everyone else to become what they are
It is my personal opinion that true evil destroys itself and that is why goodness is winning the proverbial war.