n. Any of numerous chiefly marine carnivorous fishes of the class Chondrichthyes (subclass Elasmobranchii), which are sometimes large and voracious and have a streamlined torpedolike body, five to seven gill openings on each side of the head, a large oil-filled liver, a cartilaginous skeleton, and tough skin covered with small toothlike scales.n. A person regarded as ruthless, greedy, or dishonest.n. A vicious usurer.n. Slang A person unusually skilled in a particular activity: a card shark. v. Archaic To obtain by deceitful means.verb-intransitive. To practice or live by fraud and trickery.