fidelity vs rectitude

fidelity

noun
  • Faithfulness to one's duties. 

  • Accuracy, or exact correspondence to some given quality or fact. 

  • Loyalty to one's spouse or partner, including abstention from cheating or extramarital affairs. 

  • The degree to which a system accurately reproduces an input. 

rectitude

noun
  • Conformity to the rules prescribed for moral conduct; (moral) uprightness, virtue. 

  • Straightness; the state or quality of having a constant direction and not being crooked or bent. 

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