roil·y (roi?l?)adj. roil·i·er, roil·i·est 1. Full of sediment; muddy or cloudy.2. Turbulent; agitated.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.roily (?r??l?) adj, roilier or roiliestrare cloudy or muddyCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014roil?y (?r?? li) adj. roil?i?er, roil?i?est. 1. turbid; muddy. 2. turbulent. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.