call back vs enforce

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. 

enforce

verb
  • To give strength or force to; to affirm, to emphasize. 

  • To keep up, impose or bring into effect something, not necessarily by force. 

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