nightmare

noun
night·mare | \ ˈnīt-ˌmer \

Definition of nightmare 

1 : an evil spirit formerly thought to oppress people during sleep

2 : a frightening dream that usually awakens the sleeper

3 : something (such as an experience, situation, or object) having the monstrous character of a nightmare or producing a feeling of anxiety or terror

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Other words from nightmare

nightmare adjective
nightmarish \ˈnīt-ˌmer-ish \ adjective
nightmarishly adverb

Synonyms & Antonyms for nightmare

Synonyms

agony, Gehenna, hell, horror, misery, murder, torment, torture

Antonyms

heaven, paradise

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Did You Know?

Looking at nightmare, you might guess that it is a compound formed from night and mare. If so, your guess is correct. But while the night in nightmare makes sense, the mare part is less obvious. Most English speakers know mare as a word for a female horse or similar equine animal, but the mare of nightmare is a different word, an obsolete one referring to an evil spirit that was once thought to produce feelings of suffocation in people while they slept. By the 14th century the mare was also known as a nightmare, and by the late 16th century nightmare was also being applied to the feelings of distress caused by the spirit, and then to frightening or unpleasant dreams.

Examples of nightmare in a Sentence

Mommy, I had a really scary nightmare. The party was a complete nightmare.

Recent Examples on the Web

Medical specialists worry that aside from physical ailments, the boys could experience anxiety, panic attacks, recurrent nightmares, phobias, or other symptoms of post-traumatic stress disorder in the short or long term. Navaon Siradapuvadol And Mike Ives, BostonGlobe.com, "Soccer Players and Their Coach Are on the Mend, Thailand Says," 12 July 2018 Because Gilead is a living nightmare, they were subsequently forced to plunge to their deaths in a swimming pool. Emily Yahr, chicagotribune.com, "'The Handmaid's Tale' Season 2 finale: The most shocking moments from a violent episode," 11 July 2018 Medical specialists worry that aside from physical ailments, the boys could experience anxiety, panic attacks, recurrent nightmares, phobias or other symptoms of post-traumatic stress disorder in the short or long term. New York Times, "Soccer Players and Their Coach Are on the Mend, Thailand Says," 11 July 2018 As far as consolation prizes go for the snowballing nightmare of climate change, these clouds are pretty stunning. Rachel Becker, The Verge, "How to capture the eerie nighttime clouds of climate change," 6 July 2018 Indiana veteran Jeff Staker returned from duty to see fellow soldiers become shadows of themselves, riven by nightmares, pain, and addiction. Patrik Jonsson, The Christian Science Monitor, "As war vets enter the fray, stigma lessens around cannabis," 5 July 2018 But a deal of that sort is a nightmare for America’s closest allies in the region, South Korea and Japan, who would be left at the mercy of North Korea’s short- and medium-range missiles, possibly tipped with nuclear bombs. The Economist, "Talks between America and North Korea might succeed—at a terrible price," 7 June 2018 The result was every adult child's nightmare: Mom fell before getting into bed and lay on the floor, bruised and disoriented, until morning. Melanie P. Merriman, courant.com, "My Aging Mom Didn't Want To Be A Burden. And That Was A Burden.," 30 May 2018 Their tag team was a nightmare, no beauty about it. Joe Lynch, Billboard, "'RuPaul's Drag Race' Season 10, Ep. 7: Snatch Game, Melania Trump & Mermaid Realness," 4 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'nightmare.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of nightmare

14th century, in the meaning defined at sense 1

History and Etymology for nightmare

Middle English nyghte mare, from nyghte night entry 1 + mare mare entry 3

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Phrases Related to nightmare

worst nightmare

Statistics for nightmare

Last Updated

18 Aug 2018

Look-up Popularity

Time Traveler for nightmare

The first known use of nightmare was in the 14th century

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More Definitions for nightmare

nightmare

noun

English Language Learners Definition of nightmare

: a dream that frightens a sleeping person : a very bad dream

: a very bad or frightening experience or situation

nightmare

noun
night·mare | \ ˈnīt-ˌmer \

Kids Definition of nightmare

1 : a frightening dream

2 : a horrible experience

Other words from nightmare

nightmarish \ˈnīt-ˌmer-ish \ adjective

nightmare

noun
night·mare | \ ˈnīt-ˌma(ə)r, -ˌme(ə)r \

Medical Definition of nightmare 

: a frightening or distressing dream that usually awakens the sleeper

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Comments on nightmare

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