Kowtow is a word that comes from China and it means to show a lot of respect for someone who is higher in rank than you. Imagine you are playing a game where you have a king or queen and you are a prince or princess. When you meet the king or queen in real life, you would act super respectful and maybe even bow down to them. That's like kowtowing.
Back in China a long time ago, people had to kowtow to the emperor, who was like a really important king. They had to kneel down and touch their forehead to the ground three times to show how much respect they had for the emperor. It was a really big deal and people had to do it all the time, even if they didn't want to.
Nowadays, we don't really use the word kowtow as much, but we still show respect to important people by being polite and listening to them when they talk. It's always good to be respectful, just like you would if you met a king or queen in real life.