unpredictable

UK: ˌʌnprɪˈdɪktəbl | US: ˌʌnprɪˈdɪktəbl

Definition

  1. adj. not able to be foreseen or known beforehand

  2. adj. tending to behave in ways that are not expected

Structure
un <not>predict <foretell>able <capable of>
Etymology

The word "unpredictable" combines three morphemes:

  1. "Un-" (Old English "un-"), a prefix meaning "not," negates the following root.
  2. "Predict" (Latin "praedicere," from "prae-" [before] + "dicere" [to say]), meaning "to declare in advance."
  3. "-able" (Latin "-abilis"), a suffix forming adjectives meaning "capable of."
    The term evolved in English to describe something that cannot be foretold or follows no discernible pattern.
Examples

  1. The weather in the mountains is often unpredictable.

  2. Her mood swings made her behavior unpredictable.

  3. The stock market remains highly unpredictable despite expert analysis.

  4. His unpredictable decisions kept the team on edge.

  5. The comedian's unpredictable jokes kept the audience laughing.