Dreamless describes sleep without dreams, or at least without any dreams you remember. When you have a dreamless night, you close your eyes, fall asleep, and then suddenly it's morning. There's no story, no adventure, no strange scenes playing in your mind. Just blank, restful darkness.

People experience dreamless sleep during some of the deeper stages of their sleep cycle, when their brain and body are doing important restoration work. You might sleep dreamlessly after an exhausting day of hiking or playing sports, when your body needs serious recovery time. While dreams can be entertaining or sometimes unsettling, dreamless sleep can feel especially refreshing because your mind seems to get a complete rest.

The word can also describe something that lacks dreams in the sense of hopes or ambitions. A dreamless existence might mean going through life without goals or aspirations, though this usage is less common. When writers describe a character's dreamless sleep, they're often emphasizing how deeply or peacefully that person is resting, undisturbed by the wild imagination that can activate during dreams.