When you have uncertainty, that means you're not really sure. If you missed a lot of classes and didn't study much, you may have uncertainty about whether you passed your big math test.

The noun uncertainty describes a state of doubt. You might view with uncertainty a claim that a $100 investment will return $500 by next month. Uncertainty can also involve being dependent on chance. Your uncle might have uncertainty that he'll have a job next year because his company might be closing one of its branch offices.

Definitions of uncertainty
  1. noun
    the state of being unsure of something
    synonyms: doubt, doubtfulness, dubiety, dubiousness, incertitude
    see moresee less
    the state of being certain
    show 7 types...
    hide 7 types...
    arriere pensee, mental reservation, reservation
    an unstated doubt that prevents you from accepting something wholeheartedly
    distrust, misgiving, mistrust, suspicion
    doubt about someone's honesty
    disbelief, incredulity, mental rejection, scepticism, skepticism
    doubt about the truth of something
    indecision, indecisiveness, irresolution
    doubt concerning two or more possible alternatives or courses of action
    doubt or uncertainty as to whether something is the case
    an uncertain cognitive state
    hesitation, vacillation, wavering
    indecision in speech or action
    type of:
    cognitive state, state of mind
    the state of a person's cognitive processes
  2. noun
    being unsettled or in doubt or dependent on chance
    “the uncertainty of the outcome”
    synonyms: precariousness, uncertainness
    see moresee less
    certainty, foregone conclusion, sure thing
    something that is certain
    show 8 types...
    hide 8 types...
    doubt, doubtfulness, dubiousness, question
    uncertainty about the truth or factuality or existence of something
    indefiniteness, indefinity, indeterminacy, indeterminateness, indetermination
    the quality of being vague and poorly defined
    lacking predictability
    improbability, improbableness
    the quality of being improbable
    the quality of happening accidentally and by lucky chance
    the quality of being a conclusion or opinion based on supposition and conjecture rather than on fact or investigation
    the quality of being inconclusive
    unlikelihood, unlikeliness
    the improbability of a specified outcome
    type of:
    an essential and distinguishing attribute of something or someone
Word Family

Test prep from the experts

Boost your test score with programs developed by Vocabulary.com’s experts.

  • Proven methods: Learn faster, remember longer with our scientific approach.
  • Personalized plan: We customize your experience to maximize your learning.
  • Strategic studying: Focus on the words that are most crucial for success.


  • Number of words: 500+
  • Duration: 8 weeks or less
  • Time: 1 hour / week


  • Number of words: 500+
  • Duration: 10 weeks or less
  • Time: 1 hour / week


  • Number of words: 700+
  • Duration: 10 weeks
  • Time: 1 hour / week