Nightmare
noun, verb ·Moderate ·High school level
Definitions
- 1 A very unpleasant or frightening dream.
"I had a nightmare that I tried to run but could neither move nor breathe."
- 2 a terrifying or deeply upsetting dream wordnet
- 3 Any bad, miserable, difficult or terrifying situation or experience that arouses anxiety, terror, agony or great displeasure. figuratively
"Cleaning up after identity theft can be a nightmare of phone calls and letters."
- 4 a situation resembling a terrifying dream wordnet
- 5 A demon or monster, thought to plague people while they slept and cause a feeling of suffocation and terror during sleep. archaic
"It haunted me, however, more than once, like a night-mare."
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- 6 A feeling of extreme anxiety or suffocation experienced during sleep; sleep paralysis. historical
"The Night-mare generally ſeizes people ſleeping on their backs, and often begins with frightful dreams, which are ſoon ſucceeded by a difficult reſpiration, a violent oppreſſion on the breaſt, and a total privation of voluntary motion."
- 1 To experience a nightmare. intransitive
"Brother Fary of Omaha was nightmaring the rest of the night."
- 2 To imagine (someone or something) as in a nightmare. transitive
"She was the last person I’d expected to see, although I had not expected to see anyone at all. For a moment I thought it was a nightmare, and that I was nightmaring the whole thing."
- 3 To trouble (someone or something), as by a nightmare. transitive
"THe day is broke! Melpomene, be gone; / Hag of my Fancy, let me now alone: / Night-mare my ſoul no more; Go take thy flight / Where Traytors Ghoſts keep an eternal night; […]"
Antonyms
All antonymsExample
More examples"I feel as if I've woken up from a nightmare."
Etymology
From Middle English nyghtmare, from Old English *nihtmare, equivalent to night + mare (“evil spirit believed to afflict a sleeping person”). Cognate with Scots nichtmare and nichtmeer, Dutch nachtmerrie, Middle Low German nachtmār, German Nachtmahr.
Related phrases
More for "nightmare"
Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.