Intrepid is just a fancy word for describing a person or action that is bold and brave. Super heroes are intrepid in their struggle for truth and justice.
Some synonyms are fearless, courageous, dauntless, or valiant, but the word intrepid suggests a lack of fear in dealing with something new or unknown. This adjective comes from Latin intrepidus, formed from the prefix in-, "not" and trepidus, "alarmed."