impair vs subvert

impair

verb
  • To weaken; to affect negatively; to have a diminishing effect on. 

subvert

verb
  • To overturn from the foundation; to overthrow; to ruin utterly. 

  • To upturn convention from the foundation by undermining it (literally, to turn from beneath). 

  • To pervert, as the mind, and turn it from the truth; to corrupt; to confound. 

noun
  • An advertisement created by subvertising. 

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