It's not a bad definition. You're just wrongly applying alignment to shit like sheep.
There is a huge difference between people who do bad things as a means to survive and evil. Evil is someone like Shar, who wants to destroy all of existence because she hates everything, to cause suffering and pain for no other reason than because she is spiteful. But some poor soul who is starving to death being taken in by Shar's loyal people and being offered a place where he can belong, have shelter and food, accepting to do terrible acts in the name of Shar is not by default evil...he does what he must to survive. Nobody else offered him pity or help when he was about to die in the streets so why would he feel obligated to sacrifice himself for the greater good? There are a lot of nuances here...but putting your own well being above the well being of others is not inherently evil at all.
Most people make moral judgments in different domains. I'll try a list. Note that not all people make moral judgments in all these domains. The details also vary by culture.
1. Harm: caring about others' wellbeing and avoiding harm where possible vs. being indifferent to others' suffering or actively causing unnecessary harm.
2. Fairness: showing fairness in your exchanges with others vs. ruthlessly going for your advantage.
3. Loyalty: being loyal to people who can legitimately expect it from you vs. betraying them at your whim.
4. Authority: respecting legitimate (!) authority vs. undermining it at your whim.
5. Purity: Taking proper care of your body and mind vs. wallowing in the unclean, unhealthy or disgusting.
The further you're on the right of the scale defined by the listed opposites, as the more evil you will be regarded by your society, but cultures vary greatly in some domains. The Purity domain is not usually consciously recognized as being morally relevant by our culture, but it is often invoked in fiction to mark something as evil or enhance its evil in our perception by giving it disgusting and repulsive traits. It usually works.
The most commonly recognized evil is being indifferent to others' suffering. You are expected to not cause harm, and if it can't be avoided for some reason recognized as legitimate (such as self-defense), you are expected to minimize it. Most evil game characters I've known express their evil by not recognizing the limits of the suffering they can legitimately cause by their actions.
But as the list shows, things are considerably more complex and evil characters can be interesting in rather different ways.
