1. nightmare - Noun
2. nightmare - Verb
A fiend or incubus formerly supposed to cause trouble in sleep.
A condition in sleep usually caused by improper eating or by digestive or nervous troubles, and characterized by a sense of extreme uneasiness or discomfort (as of weight on the chest or stomach, impossibility of motion or speech, etc.), or by frightful or oppressive dreams, from which one wakes after extreme anxiety, in a troubled state of mind; incubus.
Hence, any overwhelming, oppressive, or stupefying influence.
Source: Webster's dictionaryBosnia is under my skin. It's the place you cannot leave behind. I was obsessed by the nightmare of it all; there was this sense of guilt, and an anger that has become something much deeper over these last years. Paddy Ashdown
Give them pleasure - the same pleasure they have when they wake up from a nightmare. Alfred Hitchcock
All our best men are laughed at in this nightmare land. Jack Kerouac
Modern man likes to pretend that his thinking is wide-awake. But this wide-awake thinking has led us into the mazes of a nightmare in which the torture chambers are endlessly repeated in the mirrors of reason. Octavio Paz
Packing is always a nightmare. Stefanie Powers
Vision with action is a daydream; action without vision is a nightmare. Japanese Proverb