majesty: the towering greatness and splendor that belong to God.
The picture behind this word is something rising up: water swelling, a plant growing tall, a person lifting themselves high. When that height truly belongs to God, it is majesty, and the Bible reaches for this word again and again to say so. He rises up in the sea and shatters Pharaoh's army by the greatness of it. His voice thunders in it. One whole passage in Isaiah repeats three times that people will hide in caves from the splendor of his majesty when he rises to shake the earth, and a promised future shepherd of Israel is told he will lead the flock not in his own greatness but in the majesty of the LORD's name.
This is the same upward motion that, in a person, curdles into arrogance (the third meaning below). The difference is who is doing the rising. In God the height is simply true: he really is that great, so the word names glory. In a human being the height is a lie about how big he is, so the same word names pride. The Bible plays the two against each other on purpose, sometimes within the very same passage: God alone may be high, and the day of the LORD is the day every human height is brought down and his alone is left standing.
In one striking dare, God tells Job to clothe himself with majesty and grandeur, as if to say: take the thing only I can wear, and see whether you can run the world. Job cannot, and the point is made.