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1. A subtle difference in meaning, opinion or attitude
   - nuance, nicety, shade, refinement
    
2. The quality of being difficult to detect or analyse
   "you had to admire the subtlety of the distinctions he drew";
   - niceness

Derived forms: subtleties

Type of: difficultness, difficulty, fix [informal], hole [informal], import, jam [informal], kettle of fish [informal], meaning, mess [informal], muddle [informal], pickle [informal], significance, signification

Encyclopedia: Subtlety