nightmare

From Middle English nightemare, niȝtmare, 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.

• (Received Pronunciation) IPA^(key): /ˈnaɪt.mɛə/
• (General American) IPA^(key): /naɪt.mɛəɹ/, [nʌɪʔ.mɛəɹ]

  • Audio (US)

    (file)

nightmare (plural nightmares)

1. (now rare) A female demon or monster, thought to plague people while they slept and cause a feeling of suffocation and terror during sleep.
   • 1817, Walter Scott, Rob Roy:

     It haunted me, however, more than once, like the nightmare.

   • 1843, Edgar Allan Poe, ‘The Black Cat’:

     I started, hourly, from dreams of unutterable fear, to find the hot breath of the thing upon my face, and its vast weight—an incarnate Night-Mare that I had no power to shake off—incumbent eternally upon my heart!

2. A very bad or frightening dream.

   I had a nightmare that I tried to run but could neither move nor breathe.

   • July 18 2012, Scott Tobias, AV Club The Dark Knight Rises

     With his crude potato-sack mask and fear-inducing toxins, The Scarecrow, a “psychopharmacologist” at an insane asylum, acts as a conjurer of nightmares, capable of turning his patients’ most terrifying anxieties against them.

3. (figuratively) Any bad, miserable, difficult or terrifying situation or experience that arouses anxiety, terror, agony or great displeasure.

   Cleaning up after identity theft can be a nightmare of phone calls and letters.

• (demon said to torment sleepers): incubus (male demon afflicting female sleeper), succubus, night hag
• (bad dream): night terror (sleep disorder)

• nightmarish
• daymare