In Hebrew, Adoni-zedek means, My lord is righteous.
Righteous
is the translation of the Hebrew word tsedeq. We find a similar title given to another individual from Jerusalem (then called Salem) in Genesis 14:18, Melchizedek.
In the past, it may also have meant My lord is Zedek.
1 According to some sources, Tsedeq
is the name of a Canaanite deity who was worshipped in Jerusalem before the arrival of Israel.
1 As soon as Adoni-zedek, king of Jerusalem, heard how Joshua had captured Ai and had devoted it to destruction, doing to Ai and its king as he had done to Jericho and its king, and how the inhabitants of Gibeon had made peace with Israel and were among them,