inertness vs motionlessness

inertness

noun
  • Absence of the power of self-motion; inertia. 

  • Quality of being unreactive with other chemical compounds or elements. 

  • Lack of activity or exertion; habitual indisposition to action or motion 

motionlessness

noun
  • the property of being motionless 

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