Sentence examples for a runner from inspiring English sources

The phrase "a runner" is correct and usable in written English.
It can be used to refer to someone who runs, either as a sport or for exercise, or to describe a specific type of person in various contexts, such as a participant in a race.
Example: "She is a dedicated runner who trains every morning to prepare for the upcoming marathon."
Alternatives: "an athlete" or "a jogger".