pollute vs strengthen

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. 

strengthen

verb
  • To empower; to give moral strength to; to encourage; to enhearten. 

  • To make strong or stronger; to add strength to; to increase the strength of; to fortify. 

  • To reinforce, to add to, to support (someone or something) 

  • To grow strong or stronger. 

  • To substantiate; to corroborate (a belief, argument, etc.) 

  • To augment; to improve; to intensify. 

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