A workaholic is a person who is addicted to work.
The term generally implies that the person enjoys their work; it can also imply that they simply feel compelled to do it. There is no generally accepted medical definition of such a condition, although some forms of stress, obsessive-compulsive personality disorder and obsessive-compulsive disorder can be work-related.
Workaholism is not the same as working hard. Despite logging in an extraordinary amount of hours and sacrificing their health and loved ones for their jobs, workaholics are frequently ineffective employees.