WordNet sense 1 (invulnerable to fear or intimidation):

brave, dauntless, fearless, intrepid, unfearing

WordNet sense 2 (fearless and daring):

bold

WordNet sense 3 (unrestrained by convention or propriety):

barefaced, bodacious, brassy, brazen, insolent, brazen-faced, bald-faced

WordNet sense 4 (used of persons or their behavior; feeling no shame):

unashamed

WordNet sense 5 (disposed to venture or take risks):

daring, venturesome, venturous

WordNet sense 6 (willing to undertake or seeking out new and daring enterprises):

adventurous