tense vs unstable

tense

adj
  • Showing signs of stress or strain; not relaxed. 

  • Pulled taut, without any slack. 

verb
  • To apply a tense to. 

  • To make tense. 

  • To become tense. 

noun
  • Any of the forms of a verb which distinguish when an action or state of being occurs or exists. 

  • The property of indicating the point in time at which an action or state of being occurs or exists. 

  • An inflected form of a verb that indicates tense. 

unstable

adj
  • Not stable. 

  • Readily decomposable. 

  • Radioactive, especially with a short half-life. 

  • Unpredictable. 

  • Fickle. 

  • Having a strong tendency to change. 

  • Fluctuating; not constant. 

verb
  • To release (an animal) from a stable. 

How often have the words tense and unstable occurred in a corpus of books? (source: Google Ngram Viewer )