competence vs inability

competence

noun
  • The quality or state of being competent, i.e. able or suitable for a general role. 

  • The quality or state of being able or suitable for a particular task; the quality or state of being competent for a particular task or skill. 

  • The system of linguistic knowledge possessed by native speakers of a language, as opposed to its actual use in concrete situations (performance), cf. linguistic competence. 

  • the legal authority to deal with a matter. 

  • The degree to which a rock is resistant to deformation or flow. 

inability

noun
  • Lack of the ability to do something; incapability. 

  • Lack of the option to do something; powerlessness. 

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