disengagement vs undertaking

disengagement

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

  • 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. 

undertaking

noun
  • The act of one who undertakes (in either sense). 

  • A promise or pledge; a guarantee. 

  • That which is undertaken; any business, work, or project which a person engages in, or attempts to perform; an enterprise. 

  • The business of an undertaker, or the management of funerals. 

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