contumacious - disobedient
If you refuse to obey or respect authority or the law, particularly in a way that shows contempt, then you can be described as being ‘contumacious’. Such behaviour usually elicits a strongly negative reaction from others and is seen as a sign of haughtiness and insolence. This word is most commonly encountered in a legal context but is not limited to that.
The contumacious witness exasperated the judge to the extent that she threatened to charge him with contempt of court unless he started cooperating.
If Brian continues to behave contumaciously then I will have no choice but to fire him. I can’t have employees undermining my authority like that.
That particular class are so unruly that they are nearly impossible to teach. Something has to be done about their contumacious behaviour.