contumacious [kon-too-mey-shuhs, -tyoo-]
stubbornly perverse or rebellious; willfully and obstinately disobedient.
He was contumacious and refused to appear when summoned to abjure. (Henry Charlea Lea, A History of the Inquisition of the Middle Ages)
The flagrant disregard in the courtroom of elementary standards of proper conduct should not and cannot be tolerated. We believe trial judges confronted with disruptive, contumacious, stubbornly defiant defendants must be given sufficient discretion to meet the circumstances in each case. (Hugo Black, Illinois v. Allen, 397 U.S. 337, 343 (1970))
She had never before encountered a clergyman so contumacious , so indecent, so unreverend, -so upsetting. (Anthony Trollope, The Last Chronicle of Barset)
Late 16th century: from Latin contumax, contumac- (perhaps from con- ‘with’ + tumere ‘to swell’) + -ious. (Oxford English Dictionary)
Legal contexts are one area where you might encounter this fancy word for 'rebellious' or 'insubordinate' - and the link between contumacious and the law goes back to Latin. The Latin adjective contumax means 'rebellious,' or, in specific cases, 'showing contempt of court.' Contumacious is related to contumely, meaning 'harsh language or treatment arising from haughtiness and contempt.' Both contumacious and contumely are thought to ultimately come from the Latin verb tumere, meaning 'to swell' or 'to be proud.' (Merriam-Webster)