get going vs slope off

get going

verb
  • To leave, or depart. 

  • To talk passionately without interruption. 

  • To cause someone to talk passionately without interruption. 

  • To cry or bawl loudly. 

  • To arouse sexually. 

  • To excite intellectually. 

  • To begin or commence. 

slope off

verb
  • To depart quietly, without being noticed. 

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