betrothal vs disengagement

betrothal

noun
  • The fact of being betrothed; a mutual promise, engagement, or contract for a future marriage between two people. 

  • The act of betrothing. 

disengagement

noun
  • Termination of an agreement to be married. 

  • Withdrawal from combat, confrontation, or the assertion of influence. 

  • The release or separation of a chemical. 

  • A circular movement of the blade that blocks an opponent's parry. 

  • The emergence of the fetus from the birth canal. 

  • Release or detachment from a physical situation or other involvement. 

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