Noun subtlety has 2 senses
  1. nuance, nicety, shade, subtlety, refinement - 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"
    --1 is a kind of meaning, significance, signification, import
  2. subtlety, niceness - the quality of being difficult to detect or analyze; "you had to admire the subtlety of the distinctions he drew"
    --2 is a kind of difficulty, difficultness