demi-monde
noun
1- (in 19th-century France) the class of women considered to be of doubtful social standing and morality（19世纪法国的）风流女人阶层; 不正派的女人。
1.1
- a group of people considered to be on the fringes of respectable society上流社会边缘的群体, 半上流社会群体：
the demi-monde of arms deals.
从事武器交易的半上流群体。
词源
French， literally 'half-world'.