pledge vs swear

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. 

swear

verb
  • To take an oath, to promise intensely, solemnly, and/or with legally binding effect. 

  • To promise intensely that something is true; to strongly assert. 

  • To take an oath that an assertion is true. 

  • To use offensive, profane, or obscene language. 

  • To be lazy; rest for a short while during working hours. 

  • To administer an oath to (a person). 

adj
  • Dull; lazy; slow. 

  • Top-heavy; too high. 

  • Reluctant; unwilling. 

  • Heavy. 

  • Niggardly. 

noun
  • A swear word. 

  • A lazy time; a short rest during working hours (especially field labour); a siesta. 

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