Obstreperous means boisterous, noisy, aggressive, defiant.

What does defiant mean?

: full of or showing a disposition to challenge, resist, or fight : full of or showing defiance : bold, impudent defiant rebels a defiant refusal Mantor struck a defiant pose, his chin out, and rocked for a moment on the heels of his boots.—

What do you call a person who is defiant?

insubordinate, contumacious, refractory, recalcitrant, rebellious, insolent; daring.