ruinous

1 of 2

adjective

ru·​in·​ous ˈrü-ə-nəs 

1

: dilapidated, ruined

2

: causing or tending to cause ruin

ruinously adverb

ruinousness noun

ruinousness

2 of 2

noun

ru·​in·​ous·​ness

plural -es

: the quality or state of being ruinous

Synonyms of ruinous

Adjective

• disastrous
• fatal
• unfortunate
• catastrophic

Examples of ruinous in a Sentence

Adjective

The house has fallen into a ruinous state.

a ruinous miscalculation of the financial markets left them bankrupt

Recent Examples on the Web

Adjective

The unrelenting aerial attacks are hurting Russia but could be ruinous for smaller Ukraine. — Samya Kullab, Los Angeles Times, 7 Oct. 2026

The companies Suncor Energy and Exxon Mobil argue that such lawsuits must be heard in federal court and that allowing this case to proceed in state court would tie up energy companies in endless, financially ruinous lawsuits across the country. — Henry Gass, Christian Science Monitor, 5 Oct. 2026

Alvaro Bedoya, former Federal Trade Commission commissioner under President Biden, said a freeze could make the playing field more uneven by putting pressure on smaller companies in ways that could prove ruinous. — Bobby Allyn, NPR, 23 Sep. 2026

Outlier losses can deplete a significant portion of your account, causing severe financial and emotional impact, and can be detrimental and potentially ruinous to your trading career. — David Capablanca, Forbes.com, 14 Sep. 2026

Word History

First Known Use

Adjective

14th century, in the meaning defined at sense 1

Noun

1574, in the meaning defined above

Kids Definition

ruinous

adjective

ru·​in·​ous ˈrü-ə-nəs 

: causing or tending to cause ruin : destructive

ruinously adverb