Alignment can be very useful, particularly when defining some society's or group's base behavior. But the older definitions were quite cliché or even gonzo. Some more sensible definitions can increase alignment's usefulness. These are my solutions to the alignment question; you may of course disagree.
Most societies have notions of "law & regulations" and "right & wrong". Alignment does not directly determine what these are, but helps guide a society towards figuring them out.
The Good-Evil axis is about personal agency: a Good person agrees that the needs and wants of others are as valid as their own, and an Evil person does not. That does mean the Evil person is a murdering psychopath, though it could. Rather, it means they are unreliable, particularly when it really matters. When up against the wall, they will save themselves first, give up their associates, and generally view others as a means to get them out of a jam. Evil tendencies will usually need to be hidden to get along, but will manifest in small ways: blaming others, casual bigotry, a rush to punish, and so on.
The Law-Chaos axis is a bit more subtle. It is about the validity of external law. A Lawful person believes that external groups can define The Law and that this process can be valid. There are many ways to define The Law, of course, which will differ by place, but these arrangements are all valid even if one disagrees with their conclusions; they will still follow The Law. A Chaotic person accepts no external source for The Law: only their own internal code is valid. This does not mean Chaotic people are crazy. Chaotic people are perfectly able to operate in Lawful societies (which is most of them), they just never respect the authority of The Law. So they are more likely to ignore "bad" laws, or to do what they believe is "right", which will probably get them into more trouble than a Lawful person.
Neutral alignments reflect indifference or unimportance. So a Chaotic Neutral person, instead of being a complete lunatic, is simply someone who follows their personal code first and foremost; how it impacts others is of secondary concern. That makes their decisions unpredictable unless you understand their code.
I came to these definitions by wanting to answer a different question: what does it mean that most of elvish society has been canonically Chaotic Good since 1st Edition? What does a cohesive Chaotic society even look like? There are virtually no real world examples. But with these definitions, I worked towards an answer. And that answer is frankly quite mad. Elfish society must be very weird compared to what humans are used to. And I love that result!