definition of
subtlety

[1] #1 subtlety n. [nuance, nicety, shade, 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". wn

[2] #2 subtlety n. [niceness] the quality of being difficult to detect or analyze; "you had to admire the subtlety of the distinctions he drew". wn