A "hobby" is some activity that you do for fun. Here are some examples of hobbies:

painting

knitting

playing softball

collecting old cars

A person's "interests" are things that they like and are interested in. Some examples of interests:

• politics
• celebrities
• science

We often use the words "hobbies" and "interests" together, usually in that order:

If you want to get to know someone, ask them about their hobbies and interests.