Nightmare is a word that refers to a terrifying or uncomfortable dream that causes significant distress or anxiety. If you're tired of using the same word repeatedly, there are several synonyms that you can use to express the same meaning. A few synonyms for nightmare include horror, bad dream, terrifying vision, adversity, and ordeal. Other synonyms for the word nightmare are terror, fright, panic, shock, and fear. All of these synonyms can be used interchangeably to convey the same sense of fear or terror associated with a bad dream or nightmare. When you need to add more variety and emphasis to your writing, these synonyms can help you accomplish your goal.