sag off vs skive

sag off

verb
  • To skive; to fail to attend school when required to do so. 

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

  • To back off from an opponent against whom one is defending. 

  • To move too far leeward when sailing on the wind. 

  • To fall in share price. 

skive

verb
  • To avoid one's lessons or work (chiefly at school or university); shirk. 

  • To pare or shave off the rough or thick parts of. 

noun
  • An act of avoiding lessons or work. 

  • An angled cut or bevel at the edge of something. 

  • A rotating iron disk coated with oil and diamond dust used to polish the facets of a diamond. 

  • Something very easy, where one can slack off without penalty. 

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