square off vs square up

square off

verb
  • To get ready for a confrontation (debate, argument, fight). 

  • To increase the boxiness of (a design). 

square up

verb
  • to adopt a fighting stance 

  • to face (someone) in a contest 

  • to get ready for a fight 

  • To mill (blocks, inserts, etc) into precisely square condition. 

  • to pay back money that is owed 

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