escalate vs weaken

escalate

verb
  • To climb. 

  • To increase (something) in extent or intensity; to intensify or step up. 

  • In technical support, to transfer a customer, a problem, etc. to the next higher level of authority 

weaken

verb
  • To make weaker or less strong. 

  • To become weaker or less strong. 

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