Pronunciation: (rOO'u-nus), [key]
1. bringing or tending to bring ruin; destructive; disastrous: a ruinous war.
2. fallen into ruin; dilapidated: a ruinous house.
3. consisting of ruins: a ruinous city from antiquity.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.