subtlety

subtlety
/ˈsʌtltɪ; `sʌtltɪ/ n
1 [U] quality of being subtle 细微; 精细; 巧妙; 灵巧; 诡诈; 敏锐.
2 [C] subtle distinction, etc 细微的差别等.

牛津英汉双解词典