countermand vs duty

countermand

verb
  • To recall a person or unit with such an order. 

  • To counteract, to act against, to frustrate. 

  • To revoke (a former command); to cancel or rescind by giving an order contrary to one previously given. 

  • To cancel an order for (some specified goods). 

noun
  • An order to the contrary of a previous one. 

duty

noun
  • That which one is morally or legally obligated to do. 

  • The state of being at work and responsible for or doing a particular task. 

  • A tax placed on imports or exports; a tariff. 

  • The efficiency of an engine, especially a steam pumping engine, as measured by work done by a certain quantity of fuel; usually, the number of pounds of water lifted one foot by one bushel of coal (94 lbs. old standard), or by 1 cwt. (112 lbs., England, or 100 lbs., United States). 

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