Malak (verb) means to reign, be king, become king, or rule. It appears about 350 times. It describes the act of ruling — God's eternal reign, a human king's rule, or establishing a kingdom.
'The LORD reigns' is a foundational declaration (Psalm 93:1, 97:1). God's kingship predates all human monarchy. Israel's request for a human king was fraught because God was their true King. The messianic hope centers on the coming King who will reign in perfect justice forever.