answer vs knock

answer

verb
  • To be opposite, or to act in opposition. 

  • To speak in defence against; to reply to in defence. 

  • To be or act in compliance with, in fulfillment or satisfaction of, as an order, obligation, or demand. 

  • To be accountable or responsible; to make amends. 

  • To respond to a call by someone at a door or telephone, or other similar piece of equipment. 

  • To correspond to; to be in harmony with; to be in agreement with. 

  • To suit a need or purpose satisfactorily. 

  • To be or act in conformity, or by way of accommodation, correspondence, relation, or proportion; to conform; to correspond; to suit; usually with to. 

  • To make a reply or response to. 

  • To file a document in response to a complaint. 

  • To respond to satisfactorily; to meet successfully by way of explanation, argument, or justification; to refute. 

noun
  • A solution to a problem. 

  • A response or reply; something said or done in reaction to a statement or question. 

  • A document filed in response to a complaint, responding to each point raised in the complaint and raising counterpoints. 

knock

verb
  • To criticize verbally; to denigrate; to undervalue. 

  • To kick a ball towards another player; to pass. 

  • To rap one's knuckles against something, especially wood. 

noun
  • An abrupt rapping sound, as from an impact of a hard object against wood. 

  • A sharp impact. 

  • A batsman's innings. 

  • A blow or setback. 

  • Preignition, a type of abnormal combustion occurring in spark ignition engines caused by self-ignition; also, the characteristic knocking sound associated with it. 

  • Synonym of hunger knock 

  • A criticism. 

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