ruinous

comparative more ruinous · superlative most ruinous

1. Causing ruin; destructive, calamitous.
2. Extremely costly; so expensive as to cause financial ruin.

   They were forced to completely replace the roof at ruinous expense.

   1 more example

   We are rapidly reversing the economic calamity we inherited from the previous administration, including ruinous price increases and record-setting inflation, inflation like we've never had before.

   2025 September 23, Donald Trump, speech at United Nations

3. Characterized by ruin; ruined; dilapidated; as, an edifice, bridge, or wall in a ruinous state.

   Synonyms: ramshackle