What does it mean to be Good?
Goodness, beauty, truth, etc. are interchangeable in my opinion. All alternative ways of looking at the same thing.
Let me elaborate a little...
To be good is to fulfil the ends of that thing. A great knife is one that cuts well. A great person is one who uses reason accurately and uses things fittingly. He uses things to further fulfil himself and others.
Beauty is a quality of how close one thing is to its true form. Something that expresses a form well and accurately is "beautiful." Something that shows us the true form of suffering can be beautiful.
Our Existence
I think anyone can argue that existence is "good." Something that exists is infinitely closer to it's truest form compared to something which does not exist. So a person who is alcoholic and beats his wife still exists is closer to being the best fulfilment of a person compared to one which does not exist yet.
Of course, he is clearly alcoholic and is not using alcohol to boost himself and he is beating his wife, which is clearly an abuse of her, additionally as devastating to his relationship with her, indirectly harming society, which contradicts the man's social nature, etcetera.
Ultimately, the best "good" would be the highest form of existence, truth, goodness, and the most perfect "form." That, according to Thomas Aquinas, is God. Of course, you do not have to settle for this. However, it will seem to follow nicely and makes sense.
Of course, all of this is very Aristotelian which I see is pretty unpopular today.
The Subjective Argument
Maybe whoever added the words "good" and "evil" to the dictionary was a liar with a subjective view of what's good and what's evil. There aren't any objective definitions for the words "good" or "evil". Both these words have confused man ever since he believed there had been good and evil things and thoughts.