high, steep
嶬 centers on a mountain that rises sharply: something high and steep, like a towering cliff or a precipitous peak.
嶬 combines 山 (mountain) with 義, which likely contributes the sound and may carry an idea of imposing height or righteousness metaphorically applied to a steep peak.
A mountain 山 with a righteous, imposing presence 義: picture a peak so steep and high it seems to stand in judgment over the landscape.
For ギ, imagine a steep mountain so high it makes you say "Gee!" in awe: Gee -> ギ, capturing the shock of its height.
—