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English definition of “nightmare”

nightmare

noun [C]     /ˈnaɪt.meər/ US  /-mer/
B1 a very upsetting or frightening dream: a terrifying nightmare I shouldn't have watched that movie - it'll give me nightmares.Dreaming B1 an extremely unpleasant event or experience or possible event or experience: The whole journey was a nightmare - we lost our luggage and we arrived two days late. Being trapped underwater is my worst nightmare.Difficult situations and unpleasant experiencesAccidents and disasters nightmarish     /-meə.rɪʃ/ US  /-mer.ɪʃ/ adjective Serious and unpleasantNot attractive to look atInformal words for bad nightmarishly     /-meə.rɪʃ.li/ US  /-mer.ɪʃ.li/ adverb Serious and unpleasantNot attractive to look atInformal words for bad
(Definition of nightmare noun from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
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