pollute vs protect

pollute

verb
  • To corrupt or profane 

  • To violate sexually; to debauch; to dishonour. 

  • To make something harmful, especially by the addition of some unwanted product. 

  • To make something or somewhere less suitable for some activity, especially by the introduction of some unnatural factor. 

adj
  • Polluted; defiled. 

protect

verb
  • To keep safe; to defend; to guard; to prevent harm coming to. 

  • To book a passenger on a later flight if there is a chance they will not be able to board their earlier reserved flight. 

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