compunction vs penance

compunction

noun
  • A pricking of conscience or a feeling of regret, especially one which is slight or fleeting. 

penance

noun
  • A voluntary self-imposed punishment for a sinful act or wrongdoing. It may be intended to serve as reparation for the act. 

  • Any instrument of self-punishment. 

  • A sacrament in some Christian churches. 

verb
  • To impose penance; to punish. 

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