propriety
/prəʊˈpraɪətɪ/noun
(pl. -ies)［mass noun］
1- the state or quality of conforming to conventionally accepted standards of behaviour or morals（行为, 道德）正当; 得体; 合宜：
he always behaved with the utmost propriety.
他总是举止得体。
1.1
proprieties
the details or rules of behaviour conventionally considered to be correct行为规范; 礼节; 规矩, 礼仪：she's a great one for the proprieties.
她非常讲究举止规矩。
1.2
- the condition of being right, appropriate, or fitting正确, 合宜, 适当：
they questioned the propriety of certain investments made by the council.
他们质疑市政会的一些投资是否恰当。
词源
late Middle English （in the sense 'peculiarity，essential quality'）： from Old French propriete,from Latin proprietas （see PROPERTY）.