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English definition of “nightmare”

nightmare

noun [C]     /ˈnaɪtmeər/
EXPERIENCE B1 a very unpleasant experience: The traffic can be a real nightmare after 4.30.Difficult situations and unpleasant experiencesAccidents and disasters
DREAM B1 a frightening dreamDreaming
(Definition of nightmare noun from the Cambridge Learner's Dictionary © Cambridge University Press)

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