thiefy vs treacherous

thiefy

adj

  • Like a thief; thievish; thieving 

treacherous

adj

  • Exhibiting treachery. 

  • Deceitful; inclined to betray. 

  • Unreliable; dangerous. 

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