encourage vs unnerve

encourage

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

  • To spur on, strongly recommend. 

  • To foster, give help or patronage 

unnerve

verb
  • To make somebody nervous, upset, alarm, shake the resolve of. 

  • To deprive of nerve, force, or strength; to weaken; to enfeeble. 

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