call off vs renege

call off

verb
  • To recall; to cancel or call a halt to. 

  • To telephone in one's notice of a day's absence from work. 

renege

verb
  • To break a promise or commitment; to go back on one's word. 

  • In a card game, to break one's commitment to follow suit when capable. 

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