frazzle vs undermine

frazzle

verb
  • To fray or wear down, especially at the edges. 

  • To drain emotionally or physically. 

noun
  • A burnt fragment; a cinder or crisp. 

  • The condition or quality of being frazzled; a frayed end. 

undermine

verb
  • To dig underneath (something), to make a passage for destructive or military purposes; to sap. 

  • To weaken or work against; to hinder, sabotage. 

  • To erode the base or foundation of something, e.g. by the action of water. 

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