uncertainty, and its synoyms

1. The condition of being uncertain; doubt.

2. Something uncertain: the uncertainties of modern life.

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Synonyms: uncertainty, doubt, dubiety, skepticism, suspicion, mistrust

These nouns refer to the condition of being unsure about someone or something. 

• Uncertainty, the least forceful, merely denotes a lack of assurance or conviction:
    ... I regarded my decision with growing uncertainty. 
• Doubt and dubiety imply a questioning state of mind:
    ... "Doubt is part of all religion" Isaac Bashevis Singer.
    ... On this point there can be no dubiety. 
• Skepticism generally suggests an instinctive or habitual tendency to question and demand proof:
    ... "A wise skepticism is the first attribute of a good critic" James Russell Lowell. 
• Suspicion is doubt as to the innocence, truth, integrity, honesty, or soundness of someone or something:
    .. His furtiveness aroused my suspicions. 
• Mistrust denotes lack of trust or confidence, as in a person's motives, arising from suspicion:
    ... The staff viewed the consultant's hasty recommendations with mistrust.

... Am-Heritage, http://www.thefreedictionary.com/uncertainty