bemoan vs complain

bemoan

verb
  • To moan or complain about (something). 

  • To be dismayed or worried about (someone), particularly because of their situation or what has happened to them. 

complain

verb
  • To express feelings of pain, dissatisfaction, or resentment. 

  • To creak or squeak, as a timber or wheel. 

  • To make a formal accusation or bring a formal charge. 

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