Word: ruinous
Causing ruin; destructive, calamitous
Extremely costly; so expensive as to cause financial ruin. Example: They were forced to completely replace the roof at ruinous expense.
Characterized by ruin; ruined; dilapidated; as, an edifice, bridge, or wall in a ruinous state.
You can find a list of possible crossword clues for RUINOUS below.