The word appropriate has two very different meanings.

1. Appropriate is an adjective meaning suitable or proper for a situation. Appropriate behavior at a library differs from appropriate behavior at a playground. Wearing pajamas might be appropriate at a sleepover but not at school. Something inappropriate breaks the expected rules or standards for that setting.
2. As a verb, to appropriate something means to take it for your own use, often without permission or in a way that wasn't originally intended. When you appropriate your sister's favorite pen without asking, you've taken something that belongs to someone else. When a government appropriates funds, it officially sets aside money for a specific purpose, like building new schools or repairing roads.