Any bad, miserable, difficult or terrifying situation or experience that arouses anxiety, terror, agony or great displeasure.
A very bad or frightening dream.
A feeling of extreme anxiety or suffocation experienced during sleep; Sleep paralysis.
To have a nightmare.
A feeling of long-lasting ire for another, sometimes to the point of hatred, over a perceived wrongdoing; bitterness.
Rancidity, rankness.