abend vs undo

abend

verb
  • To terminate abnormally. 

noun
  • The abnormal termination of a program. 

  • Termination of a process prior to completion. 

undo

verb
  • To unfasten. 

  • To reverse the effects of an action. 

  • To impoverish or ruin, as in reputation; to cause the downfall of. 

noun
  • An operation that reverses a previous action. 

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