loan sharkn. Informal One who lends money at exorbitant interest rates, especially one financed and supported by an organized crime network.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.loan shark n (Banking & Finance) informal a person who lends funds at illegal or exorbitant rates of interest Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014loan? shark` n. Informal. a person who lends money at excessively high rates of interest; usurer. [1900?05, Amer.] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.