indulgence vs subtlety

indulgence

verb
  • to provide with an indulgence 

noun
  • An indulgent act; a favour granted; gratification. 

  • A pardon or release from the expectation of punishment in purgatory, after the sinner has been granted absolution. 

  • The act of catering to someone's every desire. 

  • The act of indulging. 

  • Tolerance. 

  • A wish or whim satisfied. 

  • Something in which someone indulges. 

subtlety

noun
  • The quality of being done in a clever way that is not obvious or not direct; the quality of being carefully thought out. 

  • The quality of being able to notice or understand things that are not obvious. 

  • An instance of being subtle, a subtle thing, especially a subtle argument or distinction. 

  • The quality of being able to achieve one's aims through clever, delicate or indirect methods. 

  • The quality of being scarcely noticeable or difficult to discern. 

  • An ornate medieval illusion dish or table decoration, especially when made from one thing but crafted to look like another. 

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