(linguistics) The quality of being fluent in a language; A person's command of a particular language.
The quality of consistently applying skill correctly in the manner of one well-practiced at it, requiring little deliberate thought to perform without mistakes
“He was one of those rare writers who could express himself verbally with a fluency that equalled his literary ability.”
“In Renaissance Italy, he became a student of Titian in Venice, liberating himself from the conventions of icon painting and developing a new fluency with brush and color.”
“I'm glad I studied abroad because it greatly enhanced my fluency in Spanish.”
fluent
(mathematics) A continuous variable, especially one with respect to time in Newton's Method of Fluxions.
“She showcased her fluentness in three different languages during the international conference.”
“In the final furlong at Doncaster the fluentness of his forward propulsion was akin to striding out between departure gates on an airport conveyor belt.”