wikipedia
Structural unemployment involves a mismatch between the sufficiently skilled workers looking for jobs and the vacancies available.
structural unemployment is a result of the dynamics of the labor market and the fact that these can never be as flexible as, e.g., financial markets. Workers are “left behind” due to costs of training and moving (e.g., the cost of selling one’s house in a depressed local economy), plus inefficiencies in the labor markets, such as discrimination or monopoly power. gen