Social justice is one of those squishy terms that is not easy to define. One thing we know for certain: social justice is not the same thing as justice, an age-old idea that was the focus of such thinkers as Aristotle, Plato, Augustine of Hippo, Aquinas, and Hume. (After all, if social justice meant the same thing as justice, the word "social" would be superfluous.)
Many years ago, while speaking to William F. Buckley, Jr. on the idea of social justice, the Nobel Prize-winning economist F.A. Hayek observed the "meaningless conception" of the term.