Fausset's Bible Dictionary
("lord of righteousness".) An Amorite king of Jerusalem, answering to the ancient king of it, Melchizedek (king of righteousness); one of many proofs that the Canaanite idolatry was an apostasy from the primitive truth of God which they once had. He headed the confederacy against Joshua, which the kings of Hebron, Jarmuth, Lachish, and Eglon also joined. Attacking Gebeon for having made peace with Israel, they in turn were attacked by Joshua, who came by forced march from Gilgal to the relief of his ally. Routed they fled to Bethhoron, thence to Azekah and Makkedah, amidst the fearful hailstorm from God, followed by the sun's standing still at Joshua's command. Brought forth from their hiding place, a cave at Makkedah to the mouth of which Joshua had caused great stones to be rolled, they had their necks trodden down by his captains, and then were slain and hung on trees until sunset (Deuteronomy 21:23), and their bodies were buried in the cave.
These files are public domain.
Fausset, Andrew R. Entry for 'Adoni-Zedek'. Fausset's Bible Dictionary. https://www.studylight.org/dictionaries/eng/fbd/a/adoni-zedek.html. 1949.