no-ac·count (n???-kount?)adj. Informal Worthless; good-for-nothing: my no-account brother-in-law.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.no-account adj worthless; good-for-nothing n a worthless person Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014no?-account` Informal. adj. 1. worthless; good-for-nothing; trifling. n. 2. a worthless person; good-for-nothing. [1835?45, Amer.] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.