Chinese Wall

Marvin hops over the edge of his retaining wall, which he built.
The Story Behind Lee Marvin’s Liberty Valance Smile|Robert Ward|January 3, 2015|DAILY BEAST
A flash of surprise and pleasure lit the fine eyes of the haughty beauty perched up there on the palace wall.
The Red Year|Louis Tracy
Kind of a reception-room in there—guess I know a reception-room from a hole in the wall.
Boys and Girls Bookshelf; a Practical Plan of Character Building, Volume I (of 17)|Various
Distance, the uncertain light, and imagination, magnified it to a high wall; high as the wall of China.
The Giant of the North|R.M. Ballantyne
He leant against the wall of his refuge, notwithstanding this boast, and licked the ice to moisten his parched lips.
The Giant of the North|R.M. Ballantyne
Undesirable inhabitants of the country are being sent away, especially the Japanese, who are more dangerous than the Chinese.
The Philippine Islands, 1493-1898, Volume XX, 1621-1624|Various

British Dictionary definitions for Chinese Wall

Chinese wall

noun

a notional barrier between the parts of a business, esp between the market makers and brokers of a stock-exchange business, across which no information should pass to the detriment of clients

an insurmountable obstacle

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012