on the level vs unfair

on the level

prep
  • Synonym of on the square (“discreet reference to freemasonry”) 

  • Honest(ly), sincere(ly), straightforward(ly), fair(ly). 

unfair

adj
  • not fair, unjust 

  • sorrowful; sad 

How often have the words on the level and unfair occurred in a corpus of books? (source: Google Ngram Viewer )