defiant
adj.showing that you refuse to obey someone or something. You use this to describe someone who is being bold and challenging toward authority.
adj.showing open resistance or bold disobedience. Often used to describe a person's attitude or physical expression when facing opposition.
“The child stood with a defiant look on his face.”
“Despite the threat of a fine, the shopkeeper remained defiant and kept his store open during the holiday.”
“The protesters remained defiant in the face of the new legislation, gathering in the central square to voice their opposition despite the heavy police presence.”
Often used predicatively after linking verbs like 'remain', 'stay', or 'look'.
“Rogers crashed an effort against the bar and Jack Wilshere’s side were defiant in defence.”
“The paper says he has fired a "defiant warning to critics".”
Borrowed from French défiant, from the verb défier. Doublet of diffident. By surface analysis, def(i) + -ant.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.