blot out vs slide off

blot out

verb
  • Used other than figuratively or idiomatically: see blot, out. 

  • To obscure. 

  • To annihilate 

  • To make indecipherable; to obliterate. 

slide off

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

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

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