buttress vs weaken

buttress

verb
  • To support something physically with, or as if with, a prop or buttress. 

  • To support something or someone by supplying evidence. 

noun
  • A brick or stone structure built against another structure to support it. 

  • Anything that supports or strengthens. 

  • A buttress-root. 

  • Anything that serves to support something; a prop. 

  • A feature jutting prominently out from a mountain or rock. 

weaken

verb
  • To make weaker or less strong. 

  • To become weaker or less strong. 

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