Suffering is bad, and the intentional or neglient creation of suffering is evil.
Those that have created suffering have done evil, and those that are currently creating suffering, or plan to create suffering are evil. The larger the suffering, the greater the evil.
Those that have done evil, but are no longer willing to do evil are not evil.
In the end, evil is a simplification that allows us to take power from those that want to create suffering without needing to know what exactly they are doing or planning.