escaping vs unstable

escaping

noun
  • The act of one who escapes; an escape. 

  • That which escapes or leaks out; an emission. 

unstable

adj
  • Readily decomposable. 

  • Not stable. 

  • 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 escaping and unstable occurred in a corpus of books? (source: Google Ngram Viewer )