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.
A person regarded as ruthless, greedy, or dishonest.
A vicious usurer.
Slang A person unusually skilled in a particular activity: a card shark.