Old English bræsen "of brass," from bræs "brass" (see brass (n.)) + -en (2). The figurative sense of "hardened in effrontery" is from 1570s (in brazen-faced), perhaps suggesting a face unable to show shame. To brazen it "face impudently" is from 1550s. Related: Brazenly.
unrestrained by convention or propriety; "the most bodacious display of tourism this side of Anaheim"- Los Angeles Times; "the modern world with its quick material successes and insolent belief in the boundless possibilities of progress"- Bertrand Russell;
