depart vs slide off

depart

verb
  • To go away from; to leave. 

  • To leave. 

  • To die. 

  • To disappear, vanish; to cease to exist. 

  • To deviate (from), be different (from), fail to conform. 

  • To set out on a journey. 

slide off

verb
  • To leave a place, a meeting, etc., without being noticed; to slip away, slip off. 

  • Used other than figuratively or idiomatically: see slide, off. 

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