shameless or impudent

brazen presumption.

made of brass.

like brass, as in sound, color, or strength.

to make brazen or bold. ?

brazen out or through, to face boldly or shamelessly

He prefers to brazen it out rather than admit defeat.

noun

assumption , audaciousness , audacity , boldness , brashness , cheek , cheekiness , chutzpah , discourtesy , disrespect , effrontery , face , familiarity , forwardness , gall , impertinence , impudency , incivility , insolence , nerve , nerviness , overconfidence , pertness , presumptuousness , pushiness , rudeness , sassiness , sauciness