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Definition of nightmare

nightmare

/ˈnaɪtˌmɛr/
night · mare
Adverb:nightmarishly
•
Plural:nightmares
•
Adjective:nightmarish
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nightmare Lexical Profile

nightmare Game Scores & Validity

• noun

1

A frightening or unpleasant dream, often accompanied by feelings of intense anxiety, helplessness, or terror.

Example

"The child woke up crying after having a vivid nightmare about being lost in the dark."

2

A terrifying, overwhelmingly difficult, or deeply unpleasant real-life experience or situation.

Example

"Navigating the airport during the holiday snowstorm turned into a logistical nightmare."

3

In Germanic and Slavic folklore, a malevolent spirit or demon thought to sit on the chest of a sleeping person, inducing feelings of suffocation and bad dreams.

Example

"Early European superstition attributed sleep paralysis to the visitations of a nightmare."

Synonyms
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Antonyms
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• Nearby Words

nightlight
nightlong
nightly
nightmare
nightmarish
nightmarishly
nightmarishness

Word Origin & Etymology

Formed in Middle English from 'night' and Old English 'mære' (an incubus or goblin), which was believed in Germanic folklore to sit upon a sleeper's chest and cause suffocation and terrifying dreams; the second element is unrelated to the word for a female horse.

Cite this Entry

Wordmom. (2026). Definition of Nightmare. In Wordmom Dictionary. Retrieved Nov 5, 2026, from https://wordmom.com/dictionary/nightmare
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