/ Dictionary / Index R roil: Meaning and Definition of Find definitions for: roil Pronunciation: (roil), [key] —v.i. to move or proceed turbulently. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: roil (Thesaurus) ROI roily Related Content Daily Word Quiz: arid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language