audacious (adj.)
1540s, "confident, intrepid, daring," from Middle French audacieux, from audace "boldness," from Latin audacia "daring, boldness, courage," from audax "brave, bold, daring," but more often "bold" in a bad sense, "rash, foolhardy," from audere "to dare, be bold." In English, the bad sense of "shameless, unrestrained by propriety" is attested from 1590s. Related: Audaciously; audaciousness.