subtlety

Noun

• the quality of being difficult to detect or analyze
  • you had to admire the subtlety of the distinctions he drew
    

• a subtle difference in meaning or opinion or attitude
  • without understanding the finer nuances you can't enjoy the humor
    
  • don't argue about shades of meaning
    

Related words

• Synonyms: 
  niceness , nuance , nicety , shade , refinement