affirm vs warrant

affirm

verb
  • To assert positively; to tell with confidence; to aver; to maintain as true. 

  • To make firm; to confirm, or ratify; especially (law) to assert or confirm, as a judgment, decree, or order, brought before an appellate court for review. 

  • To agree, verify or concur; to answer positively. 

  • To state under a solemn promise to tell the truth which is considered legally equivalent to an oath, especially of those who have religious or other moral objections to swearing oaths; also solemnly affirm. 

  • To support or encourage. 

warrant

verb
  • To guarantee as being true; (colloquial) to believe strongly. 

  • To justify; to give grounds for. 

  • To authorize; to give (someone) sanction or warrant (to do something). 

  • To guarantee (something) to be (of a specified quality, value, etc.). 

noun
  • Authorization or certification; a sanction, as given by a superior. 

  • A certificate of appointment given to a warrant officer. 

  • A judicial writ authorizing an officer to make a search, seizure, or arrest, or to execute a judgment. 

  • An option, usually issued together with another security and with a term at issue greater than a year, to buy other securities of the issuer. 

  • Something that provides assurance or confirmation; a guarantee or proof. 

  • Underclay in a coal mine. 

  • A document certifying that a motor vehicle meets certain standards of mechanical soundness and safety; a warrant of fitness. 

  • An order that serves as authorization; especially a voucher authorizing payment or receipt of money. 

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