I think good would imply that they are beating everyone who is a banger, plus most APA 5's and 6's, a lot of the 7's or just the 5s and 6s.
I had a guy that asked me to play at Chris’s one day when I was practicing on a Diamond.
He loses the very first game and since he thought he was “good” he decided to explain to me how I played the previous rack wrong.
Remember he lost but thought he was good.
I listened to his theory then decided to demonstrate what I thought good was.
I beat him every single game in 8 ball, 9 ball, and 10 ball for two solid hours. He never won a single game. Yet he had the balls to tell me I ran out the rack wrong.
Fast forward six weeks and I am practicing again same place same table.
He spots me and looks away, so I call him over and ask him if he’d like to play some. No he says I’m good.
I laughed at him and said yeah you’re good, you’re really good at racking the balls for me. Maybe another time.
He had no clue yet had the balls to tell me how to play. I prefer to let my game do the talking…