cultivate vs weaken

cultivate

verb
  • To turn or stir soil in preparation for planting. 

  • To nurture; to foster; to tend. 

  • To grow plants, notably crops. 

weaken

verb
  • To make weaker or less strong. 

  • To become weaker or less strong. 

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