sag off vs scull

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. 

scull

verb
  • To skate while keeping both feet in contact with the ground or ice. 

  • To drink the entire contents of (a drinking vessel) without pausing. 

  • To row a boat using a scull or sculls. 

noun
  • A small rowing boat, for one person. 

  • A skull cap. A small bowl-shaped helmet, without visor or bever. 

  • One of a pair of oars handled by a single rower. 

  • A light rowing boat used for racing by one, two, or four rowers, each operating two oars (sculls), one in each hand. 

  • The skua gull. 

  • A single oar mounted at the stern of a boat and moved from side to side to propel the boat forward. 

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