Here's why:
* Adjectives describe nouns: They tell us more about a person, place, or thing.
* Brave and courageous describe qualities: They describe the quality of someone who is fearless and willing to face danger.
For example, you might say:
* "The brave knight rode into battle." (Brave describes the knight.)
* "The firefighter showed courageous actions." (Courageous describes the actions.)