Words related to whale
Old English walu "ridge, bank" of earth or stone, later "ridge made on flesh by a lash" (related to weal (n.2)); from Proto-Germanic *walu- (source also of Low German wale "weal," Old Frisian walu "rod," Old Norse völr "round piece of wood," Gothic walus "a staff, stick," Dutch wortel, German wurzel "root"), from PIE root *wel- (3) "to turn, revolve." The common notion perhaps is "raised line." Used in reference to the ridges of textile fabric from 1580s. Wales "horizontal planks which extend along a ship's sides" is attested from late 13c.
"sea-unicorn, dolphin-like Arctic sea mammal" (one of the teeth of the male is enormously developed into a straight spirally fluted tusk), 1650s, from Danish and Norwegian narhval, probably a metathesis of Old Norse nahvalr, literally "corpse-whale," from na "corpse" (see need (n.)) + hvalr "whale" (see whale). If this is right, it likely was so called from its whitish color, resembling that of dead bodies. But according to nature writer Barry Lopez ("Arctic Dreams"), Winfred P. Lehmann, professor of Germanic linguistics, suggested the name was folk-etymology and said nahvalr was a West Norse term meaning "whale distinguished by a long, narrow projection."
by 1560s, perhaps mid-15c., if an isolated instance in a diary in Middle English Compendium is the same word, of uncertain origin.
The meaning "dishonest person who preys on others," though attested from 1599 (sharker "artful swindler" in this sense is from 1594), may be the original sense, later transferred to the large, voracious marine fish. If so, it is possibly from German Schorck, a variant of Schurke "scoundrel, villain," agent noun of Middle High German schürgen (German schüren) "to poke, stir."
On an old theory, the English word is from a Mayan word, xoc, which might have meant "shark." Northern Europeans seem not to have been familiar with the larger sort of sharks before voyages to the tropics began. A slightly earlier name for it in English was tiburon, from Spanish tiburón (1520s), which probably is from a native word from South America, such as Tupi uperu "shark" (source also of Portuguese tubarão, Catalan tauró).
Middle English had hound-fish (early 14c.), which probably was used of dogfish and other small sharks. The general Germanic word seems to be represented by Old Norse har (Norwegian hai, Danis haj, Dutch haai, German Hai, also borrowed in Finnish, Latvian), which is of unknown origin. French requin is literally "grimacer," from Norman requin, from Old French reschignier "to bare the teeth, grimace." An ancient Greek word for a shark was karkharias, from karkharos "sharp, jagged, biting." Latin used squalus, from the root of English whale (n.); Lithuanian ryklys is literally "swallower."
The English word was applied (or re-applied) to voracious or predatory persons, on the image of the fish, from 1707 (originally of pick-pockets); loan shark is attested from 1905. Sharkskin (1851) was used for binding books, etc. As the name of a type of fabric held to resemble it, it is recorded from 1932.
There is the ordinary Brown Shark, or sea attorney, so called by sailors; a grasping, rapacious varlet, that in spite of the hard knocks received from it, often snapped viciously at our steering oar. [Herman Melville, "Mardi"]