Definition of "discourteous"

Kirk, who succeeded Drumright, had an unusually short tour of duty in Taipei—only about a year. Despite the shortness of his duty, he left the impression of being an old sea captain who would have felt more at home barking his orders from the bridge than heading an important diplomatic mission. There was nothing civil or gentle about him, and even in talking to President Chiang, he sounded gruff and blunt. I could see that the President really didn't enjoy the envoy's company, but he remained unperturbed and discussed in a calm and friendly manner whatever had prompted the Ambassador to seek the audience. Once I heard him remark half to himself: "How could anyone be so discourteous?"

1983, James C. H. Shen, “Rejoining the Government”, in Robert Myers, editor, The U.S. & Free China: How the U.S. Sold Out Its Ally‎, Washington, D.C.: Acropolis Books Ltd., page 32