Kempes is a nickname for Mario Alberto Kempes, who used to be a very famous soccer player. He played for Argentina, which is a country in South America, and he helped them win the World Cup, which is a really big soccer tournament that happens every 4 years.
Kempes was really good at scoring goals and running around the field with the ball. He had a special talent for making goals happen, and people loved watching him play. Because he was so good, he became very popular and people started calling him by his nickname: Kempes.
Even though he doesn't play soccer anymore, people still talk about him because he was such an amazing player. They remember how he helped Argentina win the World Cup and how much fun it was to watch him play. And that's what Kempes means- it's a way to say "hey, do you remember that really great soccer player from Argentina, Mario Alberto Kempes? He was amazing!"