flu·ent 
(flənt)
(flənt)adj.
1.
a. Able to express oneself readily and effortlessly: a fluent speaker; fluent in three languages.
b. Flowing effortlessly; polished: speaks fluent Russian; gave a fluent performance of the sonata.
2. Flowing or moving smoothly; graceful: a yacht with long, fluent curves.
3. Flowing or capable of flowing; fluid.
[Latin fluēns, fluent-, present participle of fluere, to flow; see bhleu- in the Appendix of Indo-European roots.]
fluen·cy n.
fluent·ly adv.