irreverential vs unnoble

irreverential

adj
  • Not reverential. 

unnoble

adj
  • Not noble; ignoble; base. 

  • Of a metal, being at the lower end of the electrochemical series, i.e. oxidising readily. 

verb
  • To make (someone or something) no longer noble 

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