A frightening dream can be an unsettling experience that leaves us feeling uneasy or anxious even after waking up. To describe such dreams, there are several synonyms that can be used such as a nightmare, a terror, a horror, or a scare. Other words that can be used to describe frightening dreams include eerie, creepy, spooky, or unsettling. You can also use words like freaky, hair-raising, spine-chilling, or bone-chilling to describe a dream that feels particularly disturbing. No matter what word you choose to use, it's important to remember that frightening dreams are a normal part of the human experience and can often offer valuable insights into our deepest fears and insecurities.