What does disastrous mean?
Disastrous is an adjective describing events, actions, or outcomes that cause severe damage, harm, or failure. It applies to both physical calamities — floods, fires, wars — and to figurative failures, as in a disastrous interview or a disastrous investment. The word derives from "disaster," whose Latin roots mean literally "bad star," reflecting an old belief that misfortune was written in the heavens. In modern usage it is emphatic but unremarkable in tone: journalists describe policies, sporting performances, and business decisions as disastrous when their consequences prove far worse than intended. It pairs naturally with nouns such as consequences, effects, results, and mistakes, and its adverb form, disastrously, modifies verbs to signal that something went badly wrong. Because it conveys both magnitude and finality — a disastrous outcome is not merely poor but ruinous — it remains one of English's most forceful words for total failure.
adjectiveCausing great damage, harm, or failure; extremely bad or unsuccessful.
- Causing great damage, suffering, or loss; catastrophic.
- (Of an attempt, plan, or performance) failing utterly; extremely bad.
"The decision to cut the flood defences proved disastrous when the storm hit."
"The oil spill had a disastrous effect on marine life along the entire coast."
"Her first attempt at public speaking was disastrous — she forgot every line of her speech."
The word "disastrous" literally means 'ill-starred' — it descends from the Latin dis- plus astrum, so calling something disastrous originally blamed it on a bad astrological omen.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of disastrous
Disastrous comes from "disaster," borrowed into English in the late sixteenth century from Italian disastro, itself formed from Latin dis- ('away, against') and astrum ('star'). The original sense reflected astrology: an event under an unfavourable star was doomed to go wrong. The adjective disastrous appeared shortly after the noun, in the early seventeenth century, and has retained its meaning of 'bringing ruin or calamity' ever since.
Related word forms
How disastrous is actually used
Neutral in register and common in both formal journalism and everyday speech. It frequently appears with abstract nouns of outcome (consequences, results, effects) and often carries a sense of avoidable human error rather than mere misfortune.
Easily confused with disastrous
"Disaster" is the noun denoting the catastrophic event itself, while "disastrous" is the adjective describing something that causes or resembles such an event.