There is a vast, confusing and un-helpful literature that argues evil is not 'a thing' in an of itself, but merely the absence of Good, the 'privation' of Good...
But evil is a thing - what's more a very simple and clear thing: evil is the opposition to Good.
An evil an evil motivation is one that intends to oppose the Good, and evil act is one that opposes Good, and evil entity is one that actively and overall opposes the Good.
Clear enough? Simple enough? It should be.
While it may be difficult in practice to discern Good and evil - the theory can and must be absolutely clear, simple and unambiguous.
At the largest and most abstract level: God's creation and God's aims for creation are Good; to be evil is to oppose creation and its aims: evil is to be anti-creation; evil is to be against Men becoming sons and daughters of God.
In one summary; evil is what opposes the true, the beautiful, the virtuous and the harmony of these. Thus, evil is to excuse, support, propose, advocate, impose that which is false or dishonest, ugly or vile or sin-advocating.
And the greatest evil is inversion - the re-labelling of evil as Good, Good as evil - it is this inversion that makes Western modernity the most evil society ever; that fact that we sneer-at and smear beauty, truth and virtue; that we advocate and coercively-impose lies, ugliness and sin on the pretence that these are Good.
What makes is evil is quite objective; and is that evil is done officially, by our laws and regulations, by education and Establishment; that evil is subsidised propagandised and celebrated; that the mainstream mass media (which occupies and addicts most of the people most of the time) is overall and strategically working for evil and against Good.
To be evil is therefore a thing, and that thing may be active, strategic, explicit...
Of course, nothing in practice is wholly-evil - because the negation of all Goods would be instant and total destruction.
But evil properly-understood as a motivation and a goal is not just common, to serve the agenda of evil with effort and dedication... this is not just a concrete reality but evil is here-and-now common, normal, approved, rewarded, mainstream...