brazen

verbs

face with defiance or impudence
"brazen it out"
brazen
is a type of (narrower)
challenge
"I dare you!"
dare, defy

adjectives

unrestrained by convention or propriety
"an audacious trick to pull"; "a barefaced hypocrite"; "the most bodacious display of tourism this side of Anaheim"- Los Angeles Times; "bald-faced lies"; "brazen arrogance"; "the modern world with its quick material successes and insolent belief in the boundless possibilities of progress"- Bertrand Russell
audacious, bald-faced, barefaced, bodacious, brassy, brazen, brazen-faced, insolent
is derived from
brazenness
made of or resembling brass (as in color or hardness)
brazen
pertains to
brass