Words are used within our minds because we don't have the computational resources to duplicate association-bundles every time we want to think about something. It's far cheaper to use pointer variables. We bind a reference to the bundle to a much simpler name and then store the name in memory instead.

As for the omnipotence-with-rocks argument, the solution is to recognize that the question is nonsense because the concepts it uses are self-contradictory. What happens when an immovable object meets an irresistible force?