call back vs rub out

call back

noun
  • Request for a second interview or audition, following a successful initial interview. 

verb
  • To request someone's return. 

  • To telephone someone again at a more convenient time. 

  • To return to a shop or residence one has previously visited. 

rub out

verb
  • To delete or erase or remove (something) by rubbing. 

  • To kill, especially to murder. 

How often have the words call back and rub out occurred in a corpus of books? (source: Google Ngram Viewer )