encourage vs frighten

encourage

verb
  • To mentally support; to motivate, give courage, hope or spirit. 

  • To spur on, strongly recommend. 

  • To foster, give help or patronage 

frighten

verb
  • To cause to feel fear; to scare; to cause to feel alarm or fright. 

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