fearlessness       
noun [ U ] uk/ˈfɪə.ləs.nəs/ us/ˈfɪr.ləs.nəs/
 无畏,大胆
the quality of having no fear
  their fearlessness in the face of the enemy 他们在敌人面前的无所畏惧 
 You need a certain fearlessness to challenge the government. 你得有胆量才能挑战政府。 
 See: fearless
 - More examples
 - He also demonstrated fearlessness.
 - He admires West's fearlessness, and her daring to be herself.
 - Richard's skills as a general and his fearlessness in battle earned him an enviable reputation.
 - Fearlessness is not the absence of fear, but the mastery of fear.