Déformation professionnelle is a big and fancy phrase that means a person's job can change the way they see and do things in their everyday life. Let's say you are a doctor or a nurse. As you work in the hospital day after day, you see how important it is to keep people healthy and safe. When you go home, you may start thinking about ways to keep yourself and your family healthy too, like washing your hands more often or getting more exercise.
Or, imagine that you are a chef. You spend most of your time thinking about food and creating dishes that taste amazing. When you go to a restaurant or a friend's house for dinner, you might find yourself thinking about how the dishes could be improved or if the chef used the right spices or ingredients.
Déformation professionnelle is not just for doctors, nurses, and chefs - it can happen to anyone in any job. Even kids can experience it! Let's say you love playing video games. You might start thinking about how the game was made or what the game designers were thinking when they made it.
In summary, déformation professionnelle means that sometimes our jobs can change the way we see and do things in our everyday life, even when we're not working.