powerful and effective language
"his eloquence attracted a large congregation"
"fluency in spoken and written English is essential"
"his oily smoothness concealed his guilt from the police"
skillfulness in speaking or writing
"Her fluency in English made her presentation feel effortless and engaging to the entire audience."
the quality of being facile in speech and writing
"Her fluency made her legal arguments sound effortless, as if she had never stumbled over a single word during the entire trial."
The quality of smoothness of flow.
"The musician's fluency was so evident that her fingers seemed to glide effortlessly across the strings without a single hesitation."