infra dig vs libertine

infra dig

adj
  • beneath one's dignity 

libertine

adj
  • Dissolute, licentious, profligate; loose in morals. 

noun
  • One who is freethinking in religious matters. 

  • Someone (especially a man) who takes no notice of moral laws, especially those involving sexual propriety; someone loose in morals; a pleasure-seeker. 

  • Someone freed from slavery in Ancient Rome; a freedman. 

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