debilitation vs pejoration

debilitation

noun
  • The act or process of debilitating, or the condition of one who is debilitated; weakness. 

pejoration

noun
  • The act or process of becoming worse; worsening or degeneration. 

  • The process by which a word acquires a more negative meaning over time. 

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