A state of extreme (usually irremediable) ruin and misfortune:
— His policies were a disaster.

synonym: catastrophe.

An event resulting in great loss and misfortune:
— The earthquake was a disaster.

synonyms: calamity, cataclysm, catastrophe, tragedy.

Roget 735: adversity, evil etc. 619; failure etc. 732; bad luck, ill luck, evil luck, adverse luck, hard fortune, hard hap, hard luck, hard lot; frowns of fortune; evil dispensation, evil star, evil genius^†; vicissitudes of life, ups and downs of life, broken fortunes; hard case, hard lines, hard life; sea of troubles; peck of troubles; hell upon earth; slough of despond.    trouble, hardship, curse, blight, blast, load, pressure.    pressure of the times, iron age, evil day, time out of joint; hard times, bad times, sad times; rainy day, cloud, dark cloud, gathering clouds, ill wind; visitation, infliction; affliction etc. (painfulness) 830; bitter pill; care, trial; the sport of fortune.    mishap, mischance, misadventure, misfortune; disaster, calamity, catastrophe; accident, casualty, cross, reverse, check, contretemps, rub; backset^†, comedown, setback [U.S.].    losing game; falling etc. v.; fall, downfall; ruination, ruinousness; undoing; extremity; ruin etc. (destruction) 162.    ... show more

Roget 619: evil, ill, harm, hurt.   , mischief, nuisance; machinations of the devil, Pandora's box, ills that flesh is heir to.    blow, buffet, stroke, scratch, bruise, wound, gash, mutilation; mortal blow, wound; immedicabile vulnus [Lat.]; damage, loss etc. (deterioration) 659.    disadvantage, prejudice, drawback.    disaster, accident, casualty; mishap etc. (misfortune) 735; bad job, devil to pay; calamity, bale, catastrophe, tragedy; ruin etc. (destruction) 162; adversity etc. 735.    mental suffering etc. 828.    demon etc. 980.    (Evil spirit) bane, etc. 663 (cause of evil). badness, etc. 649 (Production of Evil); painfulness, etc. 830; evil doer, etc. 913.    outrage, wrong, injury, foul play; bad turn, ill turn; disservice, spoliation etc. 791; grievance, crying evil.    ... show more

Dutch: calamiteit, onheil, rampspoed, catastrofe, ecologische ramp, ramp, drama, tragedie, treurspel
Polish: cios, dramat, nieszczęście, tragedia, zguba

An act that has disastrous consequences.