concern vs disquiet

concern

verb
  • To make somebody worried. 

  • To engage by feeling or sentiment; to interest. 

  • To relate or belong to; to have reference to or connection with; to affect the interest of; to be of importance to. 

noun
  • The placement of interest or worry on a subject. 

  • The expression of solicitude, anxiety, or compassion toward a thing or person. 

  • That which affects one’s welfare or happiness. A matter of interest to someone. 

  • A worry; a sense that something may be wrong; an identification of a possible problem. 

  • A business, firm or enterprise; a company. 

  • Any set of information that affects the code of a computer program. 

disquiet

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

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

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