Directly from the relevant Wikipedia entry:
Social justice is the fair and just relation between the individual and society. This is measured by the explicit and tacit terms for the distribution of wealth, opportunities for personal activity and social privileges. In Western as well as in older Asian cultures, the concept of social justice has often referred to the process of ensuring that individuals fulfill their societal roles and receive what was their due from society. In the current global grassroots movements for social justice, the emphasis has been on the breaking of unspoken barriers for social mobility, the creation of safety nets and economic justice.
The Nazis fought for placing more barriers to economic and social mobility. Social justice activists fight for fewer.
