RPGMemes

If while acting in your own self-interest you knowingly, through action or inaction, allow others to come to harm, even indirectly, that is evil. In the same way that a character knowingly doing something that benefits others would arguably make them good. A chaotic neutral person may act on a whim or in self-interest the majority of the time, but I doubt they'd let their actions cause actual harm to others.

But trying to pigeonhole human behavior into a rigid matrix of alignments is inherently flawed, people are much more complex than that. Fortunately, DND allows the DM free reign to define that or allow it to be a grey area - in reality, "alignment" will always be fluid.