The term “scab” takes on several meanings that evolved through the centuries. In the 1590s, scab is used to describe a vile person. In the 1700s, the term is used for a person who refuses to indulge in labor unions. By the 1800s, scab is used to describe people who break strikes instigated by the labor movement.
For most strikers, common demands involve safer working environment, improved benefits, better pay, and humane working hours. In the past, however, these strikes were often ignored, and the laborers had no other choice but to go back to work for lack of financial support for their families. Labor unions then thought of a way to financially support workers on strike by allotting a small portion of their wage for dues to be used on such occasions. In this case, a scab, or strike breaker, can deter the success of a strike.
Scab can also refer to a person who lacks integrity. Scabs can exist in companies naturally, or else be hired as outside contractors. When picket lines made by strikers are crossed by these scabs, it is a display of utter lack of support by some employees for the cause, and the motivation of these workers on strike can be greatly damaged. In this case, treatment for these scabs can turn violent.
Another meaning of scab is a person who gives in to deals and compromises on labor concessions. Many labor activists believe that a strong unity amongst workers can give them the full benefits of their demands. However, compromises with the company can crack the foundation of their goals.