noun

nightmare

A frightening dream or an extremely distressing experience.

She wakes from a nightmare and turns on her bedside lamp.

Etymology

A mare was a spirit believed to oppress sleepers. Nightmare shifted from the supposed night visitor to the terrifying dream, and then to any intensely distressing experience.

More examples

  • He has nightmares about falling from a great height.
  • Losing our passports turns the vacation into a nightmare.
  • The flooded basement is a nightmare for the whole family.

Forms

nightmare · nightmares

nightmarish adjective — Extremely frightening or difficult to endure.

Similar words

ordeal
Emphasizes a painful experience to endure, not a frightening dream.
horror
Can name a terrifying experience, but also intense fear.