Alright kiddo, have you heard of the sport called cricket? It's a game played with a bat and a ball, kind of like baseball. Well, a long time ago, there were two different groups of people who played cricket.
The first group were called "gentlemen". These were rich and fancy people who played cricket as a hobby. They didn't usually get paid for playing, they just did it for fun. They wore special outfits and followed a bunch of fancy rules when they played. They thought of cricket as a polite and proper game.
The second group were called "players". These were regular people who played cricket to earn money. They weren't as fancy or wealthy as the gentlemen. They would travel around England playing cricket matches against other teams, and they would get paid for winning. They didn't care as much about the fancy rules, they just wanted to win and make money.
Over time, the two groups started playing against each other. The gentlemen would get upset because the players didn't follow all their fancy rules, and the players would get mad because they thought the gentlemen looked down on them. The two groups even had different organizations that ran their cricket games.
Eventually, the two groups merged and everyone started playing by the same rules. But people still use the terms "gentlemen" and "players" to talk about the different kinds of cricketers from a long time ago.