problem vs reply

problem

noun
  • Objection. 

  • A difficulty that has to be resolved or dealt with. 

  • A puzzling circumstance. 

  • A set of moves required to complete a climb. 

  • A question to be answered, schoolwork exercise. 

  • Difficulty in accepting or understanding or refusal to accept or understand. 

adj
  • Causing a problem; problematic; troublesome. 

  • Difficult to train or guide; unruly. 

reply

noun
  • Something given in reply. 

  • A counterattack. 

  • A document written by a party specifically replying to a responsive declaration and in some cases an answer. 

  • The answer of a figure. 

  • A written or spoken response; part of a conversation. 

verb
  • To give a written or spoken response, especially to a question, request, accusation or criticism; to answer. 

  • To act or gesture in response. 

  • To repeat something back; to echo. 

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