disquiet vs unnerve

disquiet

verb
  • To make (someone or something) worried or anxious. 

noun
  • Lack of quiet; absence of tranquility in body or mind 

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 disquiet and unnerve occurred in a corpus of books? (source: Google Ngram Viewer )