punch up vs weaken

punch up

verb
  • To beat (someone) up by punching, to fist-fight. 

  • To attack or target a group of greater power or status than oneself. 

  • To make bolder, zestier, or more exciting. 

  • To switch (a source) into the main transmission. 

weaken

verb
  • To make weaker or less strong. 

  • To become weaker or less strong. 

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