pledge vs warrant

pledge

verb
  • To make a solemn promise (to do something). 

  • To deposit something as a security; to pawn. 

  • To give assurance of friendship by the act of drinking; to drink to one's health. 

noun
  • A solemn promise to do something. 

  • The personal property so pledged, to be kept until the debt is paid. 

  • A bailment of personal property to secure payment of a debt without transfer of title. 

  • A person who has taken a pledge of allegiance to a college fraternity, but is not yet formally approved. 

  • A drinking toast. 

  • An asset or person temporarily handed over to guarantee the fulfilment of something promised, under threat of permanent loss of the thing handed over; surety, security, hostage. 

  • A promise to abstain from drinking alcohol. 

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 pledge and warrant occurred in a corpus of books? (source: Google Ngram Viewer )