An uneasy or distressing desire (for something).
An unpleasant state of mental uneasiness, nervousness, apprehension and obsession or concern about some uncertain event.
A state of restlessness and agitation, often accompanied by a distressing sense of oppression or tightness in the stomach.
Something uncertain or ambiguous.
Doubt; the condition of being uncertain or without conviction.
A parameter that measures the dispersion of a range of measured values.