DECORUM

polite or appropriate conduct or behavior

propriety in manners and conduct

"He had appreciated the decorum of the guests at this dinner party."

"Having been so violent and hostile in his youth it was intriguing to see his decorum now that he had grown up."

"This sort of decorum came natural to her having grown up with dinner parties of the rich and famous."

"The decorum of these classy ladies was in perfect contrast to the boorish men who now stood beside them. In hell their is no first class seating."