The term slacker is commonly used to refer to a person who avoids work, or (primarily in North American English) an educated person who is antimaterialistic and viewed as an underachiever. Slackers are also known as loakes.
While use of the term slacker for one who shirks work dates back to about 1790 or 1898 depending on the source, it achieved a boost in popularity after its use in the films Back to the Future and Richard Linklater's Slacker.
A slacker may also be a person who is in fact suffering from depression. The person may have suffered from psychological trauma that has resulted in their lack of motivation. For example, post traumatic stress disorder commonly causes individuals to behave as slackers. For the depressed individual, correct identification of the reasons behind their behaviour is the first step to them seeking treatment and recovering.