To shanghai is (1) to kidnap someone for service as a sailor, especially by drugging them or using force; (2) to use fraud compel someone to do something; or (3) to kidnap. Inflected, the verb makes shanghaied and shanghaiing. The s is uncapitalized.
The word developed in the middle 19th century on the west coast of the United States, where experienced sailors were in short supply. Exactly why shanghai became the word for forcing a sailor into service remains a mystery, but the prevailing theory is that it came about because Shanghai was a common destination of merchant vessels based in places like San Francisco and Seattle.
Use of the word peaked in the middle 20th century and has been in decline since around 1960. There’s a good chance the word will fade from the language as Shanghai, the city, becomes less and less an exotic foreign place in the minds of Westerners.
“Mee dear friend Jim put a knock-me-out drop into your Manhattan cocktail. It’s a capsule filled with a drug. You were shanghaied, son,” said the Captain, blandly. [Moran of the Lady Letty: a story of adventure off the California coast, Frank Norris (1898)]
“There’s property there he comes into under his father’s will; an’ I’ll find him an’ take him back, if I’ve got to shanghai him.” [South Sea Shipmates, John Arthur Barry (1914)]
It made them ripe for revolt, drove them to lawless acts, as their shanghaiing and the brutality of the officers could not have done. [The Blood Ship, Norman Springer (1922)]
Aldo Icardi, former lieutenant in the Office of Strategic Services, denounced last night Defense Department efforts to “shanghai” him back to Italy to stand trial for the assassination of his wartime superior. [New York Times (1951)]
Besides, they said, the law hardly covers extradition for shanghaiing a Persian. [Eugene Register-Guard]
During the Civil War, things nearly came to blows when the Americans intercepted the British mail packet Trent and shanghaied two Confederate diplomats on their way to Europe to raise support. [Telegraph (2010)]