villainly vs viperous

villainly

adj

  • Characteristic of a villain. 

adv

  • In the manner of a villain. 

viperous

adj

  • venomous, malicious or treacherous 

  • of or pertaining to a viper 

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