Synonyms for Fearless (same or very similar meaning)
WordNet sense 1 (invulnerable to fear or intimidation):
audacious, brave, dauntless, intrepid, unfearingWordNet sense 2 (fearless and daring):
boldWordNet sense 3 (oblivious of dangers or perils or calmly resolute in facing them):
unafraidFrom the ODE community, based on WordNetadd/edit