General synonyms:
* Courageous
* Daring
* Bold
* Valiant
* Gallant
* Heroic
* Intrepid
* Fearless
* Audacious
* Stouthearted
* Spirited
More specific synonyms:
* For a specific situation: Resolute, steadfast, determined, unwavering
* For facing danger: Fearless, undaunted, dauntless
* For standing up for beliefs: Principled, righteous, steadfast
* For overcoming adversity: Resilient, tenacious, strong
The best synonym for "brave" will depend on the specific situation you are describing.