Meaning

noun any of numerous elongate mostly marine carnivorous fishes with heterocercal caudal fins and tough skin covered with small toothlike scales

noun a person who is ruthless and greedy and dishonest

noun a person who is unusually skilled in certain ways

originFrom Middle English shark (used by Thomas Beckington in 1442 to refer to a kind of fish), of uncertain origin. Most likely from a semantic extension of the German-derived shark (“scoundrel”), see below. The fish was originally called a dogfish or haye in English and Middle English. Its name in Old English is unknown, although some uses of the word hranfisċ that do not appear to carry the sense of…

Etymology from Wiktionary, CC BY-SA 3.0