-Tzedakah (צְדָקָה) means "righteousness." This word deals with "relational" or "inter-personal" characters. In the HB, God is righteous, and God's righteousness is important.
-Mishpat (מִשְׁפָּט) means "fairness" or "justice" in human lives, especially in the matters of social justice. This word also means a judgment and involves a legal claim. Other judgment-related Hebrew words are shapat, din, or riv. For more, go here.