fluency
/ˈfluːənsɪ/noun
mass noun
1- the quality or condition of being fluent, in particular流畅, 流利, 尤指：
1.1
- the ability to speak or write a particular foreign language easily and accurately外语说写流利（或流畅）的能力：
fluency in Spanish is essential.
流利的西班牙语是绝对必要的。
1.2
- the ability to express oneself easily and articulately流畅的表达能力。
1.3
- gracefulness and ease of movement or style（动作, 风度）优美自如：
the horse was jumping with breathtaking fluency.
马的跳跃动作之优美, 令人惊叹。
词源
early 17th cent.: from Latin fluentia, from fluere 'to flow'.