hard worker; industrious person
A straightforward noun describing someone who works diligently. Often used positively, but can also imply someone who works too much depending on context.
She is a real hard worker and stays at work late every day.
うちの父は働き者で、休みの日も何かしている。
My father is an industrious person; even on his days off he's doing something.
He's known in the neighborhood as a hard worker.
She's the hardest worker among the employees.
He has long been known as a hard worker.