The state of being difficult, or hard to do.
Physical danger from the environment, especially with risk of drowning
An obstacle that hinders achievement of a goal.
An objection.
An awkward situation or quarrel.
That which cannot be easily understood or believed.
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.