evil is an abstract term, a relative property that can be given to an action, a person, a way of thinking.
Evil cannot exist without a relative tie to something.
But by distilling pieces from the way it is used, you can form a quasi-evil. a semi-evil.
I call it mini-me! (oh wait)
Anyway, evil creatures are creatures who want destruction, harm, pain and all kinds of suffering. Or any combination.
Evil acts are acts of either hurt, malicious intent, destruction, mental or physical pain, ...
Evil is just an abstract grouping of properties that seem possibly or in reality damaging or negative towards the person using the term. And therefor highly relative.