I’m afraid I cant give you a dictionary like answer or set of definitions.

I think it’s also in one of Greg’s many videos: go listen to as much live performances as you can (if conditions permit these days). Don’t forget to have fun and enjoy the performance – but also really listen. What aspects of the sound do you like, what aspects can you find back in your own playing …

As I see it, we all develop our own understanding of what a “good sound” is. It is also very personal and also depending on the kind of music your’re playing. A lead trumpet in a bigband sounds very different from the trumpets in a symphonic orchestra. The keyword here is “different”, it is not as in better or worse.

Probably raising yet more questions than giving answers …