Shark is an interesting word, appearing much later than one might expect and with an unknown origin. The word apparently was used, and perhaps coined, by sailors on John Hawkins’s 1568-69 expedition. This expedition returned a specimen of the fish to London. Where they caught the fish is not recorded, but the trip was one to the Caribbean and was famous for a battle with the Spanish fleet off Veracruz in Mexico. From a 1569 selection in Black-Letter Ballads and Broadsides, published in 1867.
Ther is no proper name for it that I knowe, but that sertayne men of Captayne Haukinses doth call it a sharke.
It has been suggested by some that the word derives from the Mayan word for the fish, xoc, pronounced /showk/. Usually such exotic sources must be treated with skepticism, but given the destination of the Hawkins’s expedition, it is possible that the sailors adopted a local Indian word for the fish.
Some have also pointed out the similarity to the German (Austrian dialect) word Schirk, meaning a sturgeon, but there is no known connection and the similarity is undoubtedly coincidence.
There is, however, another German connection with the word shark. The sense of the word meaning a disreputable person who preys upon others is probably from the German Schurke, meaning scoundrel or villain. This sense appears in English in 1599 and was probably an adoption of the German word, altered by English folk etymology to become shark, in allusion to the fish and its predatory habits. From Ben Jonson’s 1599 The Comicall Satyre of Every Man Out of His Humor:
Charac., Shift. A Thredbare Sharke. One that neuer was Soldior, yet liues vpon lendings. His profession is skeldring and odling, his Banke Poules, and his Ware-house Pict-hatch.
(Source: Oxford English Dictionary, 2nd Edition)
Copyright 1997-2015, by David Wilton