[ roo-uh-nuhs ]
/ ˈru ə nəs /


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.

Origin of ruinous

1350–1400; Middle English ruynouse < Latin ruīnōsus, equivalent to ruīn(a) ruin + -ōsus -ous
Related forms Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for ruinous

British Dictionary definitions for ruinous


/ (ˈruːɪnəs) /


causing, tending to cause, or characterized by ruin or destructiona ruinous course of action
Derived Formsruinously, adverbruinousness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for ruinous



late 14c., "going to ruin," from Old French ruinos (Modern French ruineux) or directly from Latin ruinosus "tumbling down, going to ruin," from ruina (see ruin (n.)). Meaning "causing ruin" is from mid-15c. Related: Ruinously.

Online Etymology Dictionary, © 2010 Douglas Harper