It’s Uncle Marvin’s unpredictability that makes family functions so interesting — you just never know what he’s going to do! Unpredictability is the trait of doing things in a way that is irregular and cannot be predicted.

Unpredictability contains the word predictability, which describes the quality of doing things in a regular way, time after time. Unpredictability is the opposite of predictability. Because Uncle Marvin is so marked by unpredictability, you never bring your friends to family parties, fearing that Uncle Marvin might do something wacky at any moment. Unpredictability can be exciting, but it can also be scary or unpleasant never knowing what someone is going to do next.

Definitions of unpredictability
  1. noun
    lacking predictability
    see moresee less
    the quality of being predictable
    type of:
    precariousness, uncertainness, uncertainty
    being unsettled or in doubt or dependent on chance
  2. noun
    the quality of being guided by sudden unpredictable impulses
    synonyms: capriciousness
    see moresee less
    type of:
    changefulness, inconstancy
    the quality of being changeable and variable
  3. noun
    the trait of being unpredictably irresolute
    synonyms: volatility
    see moresee less
    type of:
    irresoluteness, irresolution
    the trait of being irresolute; lacking firmness of purpose
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