Invidia is a big word that means feeling very jealous or envious of someone else's things or skills.
Imagine you have a friend who always gets really good grades in school and your grades are not as good. Sometimes, you might feel bad and wish you had their grades instead. This feeling of wanting what someone else has is called invidia. It can make you feel angry or upset towards your friend even though they did nothing wrong.
It's okay to feel invidia sometimes, but it's important to learn how to handle these feelings in a healthy way. You can try talking to someone you trust about how you feel, or focusing on things you are good at and enjoy doing. Remember that everyone has different strengths and weaknesses, and it's important to be proud of what makes you special too!