1.  audacious(s = adj.all) brave, dauntless, fearless, hardy, intrepid, unfearing - invulnerable to fear or intimidation; "audacious explorers"; "fearless reporters and photographers"; "intrepid pioneers"
Derived forms noun audaciousness₁, noun audacity₁

2.  audacious(s = adj.all) bald-faced, barefaced, bodacious, brassy, brazen, brazen-faced, insolent - unrestrained by convention or propriety; "an audacious trick to pull"; "a barefaced hypocrite"; "the most bodacious display of tourism this side of Anaheim"; "bald-faced lies"; "brazen arrogance"; "the modern world with its quick material successes and insolent belief in the boundless possibilities of progress"
Derived forms noun audaciousness₂, noun audacity₂

3.  audacious(s = adj.all) daring, venturesome, venturous - disposed to venture or take risks; "audacious visions of the total conquest of space"; "an audacious interpretation of two Jacobean dramas"; "the most daring of contemporary fiction writers"; "a venturesome investor"; "a venturous spirit"
Derived forms noun audaciousness₁, noun audacity₁

1.  Daring; spirited; adventurous. [1913 Webster]
"As in a cloudy chair, ascending rides
Audacious." [1913 Webster]

2.  Contemning the restraints of law, religion, or decorum; bold in wickedness; presumptuous; impudent; insolent. Milton. [1913 Webster]

3.  Committed with, or proceedings from, daring effrontery or contempt of law, morality, or decorum. Shak. [1913 Webster]

audacious, adj.
1 daring, bold.
2 impudent.

Derivative:
audaciously adv. audaciousness n. audacity n.

Etymology:
L audax -acis bold f. audere dare

N  courage, bravery, valor, resoluteness, boldness, spirit, daring, gallantry, intrepidity, contempt of danger, defiance of danger, derring-do, audacity, rashness, dash, defiance, confidence, self-reliance, manliness, manhood, nerve, pluck, mettle, game, heart, heart of grace, spunk, guts, face, virtue, hardihood, fortitude, intestinal fortitude, firmness, heart of oak, bottom, backbone, spine, resolution, bulldog courage, prowess, heroism, chivalry, exploit, feat, achievement, heroic deed, heroic act, bold stroke, man, man of mettle, hero, demigod, Amazon, Hector, lion, tiger, panther, bulldog, gamecock, fighting-cock, bully, fire eater, courageous, brave, valiant, valorous, gallant, intrepid, spirited, spiritful, high-spirited, high-mettled, mettlesome, plucky, manly, manful, resolute, stout, stout-hearted, iron-hearted, lion-hearted, heart of oak, Penthesilean, bold, bold-spirited, daring, audacious, fearless, dauntless, dreadless, aweless, undaunted, unappalled, undismayed, unawed, unblanched, unabashed, unalarmed, unflinching, unshrinking, unblanching, unapprehensive, confident, self-reliant, bold as a lion, bold as brass, enterprising, adventurous, venturous, venturesome, dashing, chivalrous, soldierly, heroic, fierce, savage, pugnacious, strong-minded, hardy, doughty, firm, determined, dogged, indomitable, up to, up to the scratch, upon one's mettle, reassured, unfeared, undreaded, one's blood being up, courage sans peur, fortes fortuna adjuvat, have I not in my time heard lions roar, I dare do all that may become a man, male vincetis sed vincite, omne solum forti patria, self-trust is the essence of heroism, stimulos dedit oemula virtus, strong and great, a hero, teloque animus proestantior omni, there, is always safety in valor, virtus ariete fortier.

N  insolence, haughtiness, arrogance, airs, overbearance, domineering, tyranny, impertinence, sauciness, flippancy, dicacity, petulance, procacity, bluster, swagger, swaggering, bounce, terrorism, assumption, presumption, beggar on horseback, usurpation, impudence, assurance, audacity, hardihood, front, face, brass, shamelessness, effrontery, hardened front, face of brass, assumption of infallibility, saucebox, insolent, haughty, arrogant, imperious, magisterial, dictatorial, arbitrary, high-handed, high and mighty, contumelious, supercilious, overbearing, intolerant, domineering, overweening, high-flown, flippant, pert, fresh, cavalier, saucy, forward, impertinent, malapert, precocious, assuming, would-be, bumptious, bluff, brazen, shameless, aweless, unblushlng, unabashed, brazen, boldfaced-, barefaced-, brazen-faced, dead to shame, lost to shame, impudent, audacious, presumptuous, free and easy, devil-may-care, rollicking, jaunty, janty, roistering, blustering, hectoring, swaggering, vaporing, thrasonic, fire eating, full of sound and fury, with a high hand, ex cathedra, one's bark being worse than his bite, beggars mounted run their horse to death, quid times? Caesarem vehis, wagahai wa (expressing superiority).