/ Dictionary / Index R ruinous: Meaning and Definition of Find definitions for: ru•in•ous Pronunciation: (r'u-nus), [key] — adj. bringing or tending to bring ruin; destructive; disastrous: a ruinous war. fallen into ruin; dilapidated: a ruinous house. consisting of ruins: a ruinous city from antiquity. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ruinous (Thesaurus) ruination Ruisdael Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language