"to drug or otherwise render a man unconscious and ship him as a sailor on a vessel wanting hands," 1854, American English, from the practice of kidnapping to fill the crews of ships making extended voyages, such as to the Chinese seaport of Shanghai. Transferred or general sense of "to constrain, compel" is by 1919.
Chinese seaport, literally "by the sea," from Shang "on, above" + hai "sea." In mid-19c., the name given to a long-legged breed or type of hens, in great vogue at the time, supposed to have come from there. Hence the old U.S. slang senses relating to long, tall persons or things. Forming a "person from" word for it has challenged English. For a time mid-20c., Shanghailander was in jocular use.
updated on August 03, 2022