Adjective: Describes a person or their speech/writing as smooth, effortless, and natural in a particular language.
* Example: "She is a fluent speaker of French."
Noun: Refers to the state of being fluent.
* Example: "Her fluency in Spanish is impressive."
It's important to note that "fluent" is rarely used as a noun on its own. It usually appears in the phrase "fluency."