shark

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of numerous cartilaginous fishes of the subclass Elasmobranchii that are chiefly carnivorous and marine. Sharks have a streamlined torpedolike body, five to seven gill openings on each side of the head, a large oil-filled liver, and tough skin covered with small toothlike scales.
• noun Informal A person, such as a loan shark, who takes advantage of the misfortune of others for personal gain.
• noun Informal A person unusually skilled in a particular activity.
• intransitive verb To obtain by deceitful or underhand means.
• intransitive verb To take advantage of others for personal gain, especially by fraud and trickery.

from The Century Dictionary.

• To play the shark or needy adventurer; live by one's wits; depend on or practise the shifts and stratagems of a needy adventurer; swindle: sometimes with an impersonal it: as, to shark for a living.
• To pick up; obtain or get together by sharking: with up or out.
• noun A selachian of the subclass Plagiostomi, of an elongate form, with the pectoral fins moderately developed, the branchial apertures lateral, and the mouth inferior (rarely terminal).
• To fish for or catch sharks.
• noun A sharper; a cheat; a greedy, dishonest fellow who eagerly preys upon others; a rapacious swindler.
• noun The sharp practice and petty shifts and stratagems of a swindler or needy adventurer.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb obsolete To pick or gather indiscriminately or covertly.
• intransitive verb To play the petty thief; to practice fraud or trickery; to swindle.
• intransitive verb To live by shifts and stratagems.
• noun (Zoöl.) Any one of numerous species of elasmobranch fishes of the order Plagiostomi, found in all seas.
• noun colloq. A rapacious, artful person; a sharper.
• noun obsolete Trickery; fraud; petty rapine.
• noun See under Basking, Liver, etc. See also Dogfish, Houndfish, Notidanian, and Tope.
• noun the sand shark.
• noun See Hammerhead.
• noun See Cestraciont.
• noun the eggcase of a shark; a sea purse.
• noun Same as Angel fish (a), under Angel.
• noun a large, voracious shark. See Thrasher.
• noun a huge harmless shark (Rhinodon typicus) of the Indian Ocean. It becomes sixty feet or more in length, but has very small teeth.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun informal, derogatory A sleazy and amoral lawyer; an ambulance chaser.
• noun informal A relentless and resolute person or group, especially in business.
• noun informal A very good poker or pool player.
• noun A person who feigns ineptitude to win money from others.
• verb obsolete To steal or obtain through fraud.
• verb obsolete, intransitive To play the petty thief; to practice fraud or trickery; to swindle.
• verb obsolete, intransitive To live by shifts and stratagems.
• noun A scaleless, predatory fish of the superorder Selachimorpha, with a cartilaginous skeleton and 5 to 7 gill slits on each side of its head.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb play the shark; act with trickery
• noun any of numerous elongate mostly marine carnivorous fishes with heterocercal caudal fins and tough skin covered with small toothlike scales
• verb hunt shark
• noun a person who is ruthless and greedy and dishonest
• noun a person who is unusually skilled in certain ways