A player rated 900 was beating by a 1200 and says at the end of the game, "You are a good player!" So to refine the question, what is the minimum required chess knowledge to be considered a good player? Perhaps he know the Lucena and Philador rook endings; basic mating positions from Bobby's book for beginners; have a few lines memorized etc.
What is a good chess player?
This is completely subjective. You find ~1500 to be good, a 2000 would find 1800+ to be good, a GM may find only 2400+ good and the top 10 in the world probably look down on a 2700 rating.

The best player makes the best possible move in every position. The best move can only be determined after a complete analysis af the position. Every possible move has to be rated on a scale of 1 to 10. Every potential problem has to be adressed.

A good chess player is one that practices proper chess ettiqutte and sportsmanship.
On a more serious note, Feygooner is completely right. There are no specific requirements to be considered "good" or "strong" in chess because it's all subjective. If there is a minimum required chess knowledge to be considered a "good" player, it would be the rules of the game.

A good player is someone who gives me a challenge before i beat them.
A very good player is someone who usually beats me.
A great player is someone who always beats me and then can replay the game from memory and show me where i went wrong.

What is a good chess player?
1. one that washes their hands after leaving the bathroom/restroom
2.One that does not cheat on their spouse.
3. Does not use profanity, at least not in public or on chess.com
4.Likes to win but if not, plays just for the joy of the game and for the friends they meet here! man, am I sucking up?

Surely, if you want to know something or discuss something - the first thing to do is search for the topic? Is it considered 'not the thing' to resurrect an older topic? Is it preferable to start a fresh one? There should be a book of etiquette for chess.com. I just don't understand half the comments - so many people just seem to enjoy having a pop at others and I can't even work out why - unless there's history - but newbies don't know about that and so it is all a bit confusing.

OK many thanks for taking the time - I didn't know the half of that. Yes, I am a normal person - ha. So thanks for the slack cut also.

Who knows. My daughter has complained about being able to throw javelin much better while training than in competitions. I told her a quote by Tarrasch: "being a good player isn't enough, besides you must play well". Well, I doubt she was listening to me anyway.

Surely, if you want to know something or discuss something - the first thing to do is search for the topic?
Ziryab isn't a noob so he wouldn't ask this, and even so, his post was an answer not a question.
I try to know the answer before I ask the question. It helps me discern when people are lying.
What is a good chess player?