A Hardworking individual refers to someone who works with diligence and commitment. 

There is no substitute for hard work. Unless you are willing to drench yourself in your work beyond the capacity of the average man, you are just not cut out for positions at the top. Hard work is painful when life is devoid of purpose. But when you live for something greater than yourself and the gratification of your own ego, then hard work becomes a labor of love.

A 1993 paper by Ericsson, Krampe, and Tech-Romer regarding deliberate practice in which the researchers argue that success is usually built upon purposeful, thoughtful and intense efforts to improve performance over about 10,000 hours. This is true; hard work does pay off. The Beatles got to be so good because they had to perform their music four hours a day (eight days a week) during their two year stint in Hamburg. Bobby Fischer became a grandmaster at chess after years of honing his skills at the Brooklyn Chess Club.