A “one trick pony” is one of my favourite slang terms in spoken English.A “Pony” is an animal a bit similar to a horse. In the old days,
some rich parents bought their kids a pony to play with. I imagine it’s similar to some of today’s parents buying their kids a BMW or some other sports car. I guess that these ponies were supposed to be fun for kids. Kids could ride on them and play with them. Trainers could teach the ponies “tricks”.
If some pony wasn’t well trained or very talented, they could only do one special trick. If a pony could only do one trick, it’s considered to be a bad thing.
In modern spoken English, we use this term, “one trick pony” to describe a person who can only do one thing well, or has only one skill. Here are some useful examples:
1. He got very rich because of investing in the stock market. He admits he’s a one trick pony because that’s the only way he knows how to make money, but he’s proud of it because it works so well for him.
2. He’s a great football player because he can score goals. He’s terrible at defence and all other parts of the game. He’s pretty much a one trick pony.
3. Girls love him when they see him at the bar because he’s tall and athletic, but they usually don’t want to date him seriously because he’s kind of stupid and boring to talk to. I think most girls believe he’s a bit of a one trick pony.