What does nightmare mean?
A nightmare is a deeply unpleasant or frightening dream, typically involving fear, anxiety, or a sense of helplessness. The word is also used figuratively for any experience that is so difficult, stressful, or chaotic that it seems almost unreal. People describe complicated travel, confusing procedures, or unexpected problems as a “nightmare,” often with modifiers such as “absolute,” “logistical,” or “worst.” Its figurative use conveys both the severity of a situation and a sense that it is overwhelming and hard to control. Although the expression is widely used in everyday conversation, it can sound emphatic or informal. A nightmare is more than an ordinary bad dream: it implies a particularly intense experience, either while sleeping or in waking life.
A very unpleasant or frightening dream, or an experience that is extremely difficult and distressing.
"He described the interview as a nightmare."
The figurative use is common in both formal and informal English and often emphasizes extreme difficulty or stress.
To experience a nightmare, or to describe an experience as extremely difficult or distressing.
"The team nightmareed through the final round."
The verb is informal and much less common than the noun; it is often used in the expression “nightmare through” or followed by an activity.
The plural is formed by adding -s.
"The child had recurring nightmares."
The word once described a goblin believed to sit on a sleeper's chest, turning a frightening old belief into a word still used for our worst waking experiences.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of nightmare
The modern word developed from Old English nihtmare, literally “night-mare.” In medieval belief, a mare was a goblin or demon thought to sit on a sleeping person and cause distress. The form had developed into the modern English word by the Middle English period. The modern figurative sense, meaning an extremely difficult or distressing situation, is a later extension of the original meaning of a frightening dream.
Related word forms
How nightmare is actually used
The expression is common in informal speech and writing when describing especially difficult circumstances. In the extended sense, it often suggests a situation is so troublesome or overwhelming that it feels impossible to manage.
Easily confused with nightmare
A nightmare is a frightening or intensely unpleasant dream or experience; it is not the ordinary act of dreaming.