adjective
calamitous
kuh-LAM-ih-tus/kəˈlæmɪtəs/
Causing or involving great disaster or distress.
The calamitous flood sweeps away homes and destroys the harvest.

Etymology
Calamitas meant damage or misfortune; its adjective could describe something destructive or liable to disaster. The selected meaning emphasizes causing that harm. The noun's deeper origin is obscure.
In context
a paving machine fell into the net and it carried 10 workers to their death. That's a tremendous tragedy. NARRATOR: Despite this calamitous accident
More examples
- A calamitous error left the entire archive unreadable.
- The drought had calamitous consequences for the region.
- Their poorly planned retreat became a calamitous defeat.
Forms
calamitous
calamity noun — An event causing great damage or distress.
Similar words
- unfortunate
- Can describe a minor setback, while calamitous implies severe disaster.