bump off vs stop someone's clock

bump off

verb
  • To kill, especially to murder. 

  • To cut class; to play truant. 

stop someone's clock

verb
  • To kill someone. 

  • To clean someone's clock; to make incapable of action; to thwart. 

  • Used other than figuratively or idiomatically: see stop, clock. 

How often have the words bump off and stop someone's clock occurred in a corpus of books? (source: Google Ngram Viewer )