NIGHTMARE

[noun] [C] - a very upsetting or frightening dream, or (figurative) an extremely unpleasant event or experiencea terrifying nightmare(figurative) The worst nightmare for many people would be to be trapped in a car at an accident.(figurative) An earthquake under a major city would be a nightmare (scenario).(figurative) The whole journey was a nightmare - we lost our luggage and we arrived two days late.