engage vs pledge

engage

verb
  • To guarantee or promise (to do something). 

  • To enter into conflict with (an enemy). 

  • To come into gear with. 

  • To enter into (an activity), to participate (construed with in). 

  • To draw into conversation. 

  • To mesh or interlock (of machinery, especially a clutch). 

  • To attract, to please; (archaic) to fascinate or win over (someone). 

  • To engross or hold the attention of; to keep busy or occupied. 

  • To arrange to employ or use (a worker, a space, etc.). 

  • To bind through legal or moral obligation (to do something, especially to marry) (usually in passive). 

  • To enter into battle. 

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. 

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