push off vs slope off

push off

verb
  • To go away; to get lost. 

  • To delay, postpone, put off, push back. 

  • to commit a foul by pushing against an opponent to both accelerate more quickly and push the opponent in the opposite direction. 

slope off

verb
  • To depart quietly, without being noticed. 

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