subtlety
/ˈsʌtltɪ/noun
(pl.-ies)［mass noun］
1- the quality or state of being subtle微妙; 细致, 精巧; 敏锐：
the textural subtlety of Degas.
德加作品的巧妙。
1.1
- count noun a subtle distinction, feature, or argument细微区别（或特征）; 缜密的论证：
the subtleties of English grammar.
英语语法的细微差别。
词源
Middle English: from Old French soutilte, from Latin subtilitas, from subtilis 'fine, delicate' （see SUBTLE）.