steep, craggy, rugged
嵯 centers on steep, rugged terrain: a mountain that is craggy and difficult to climb.
嵯 combines 山 (mountain) with 差, which likely contributes the sound and may suggest unevenness or difference, fitting the idea of a rugged, irregular mountain.
A mountain 山 with a difference 差: its slopes are uneven, steep, and craggy.
For サ, imagine a rugged mountain so steep that climbers sigh "sah…" in exhaustion: sah -> サ.
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