steep, lofty
嶂 centers on a mountain that rises sharply and steeply, like a towering natural wall. The idea of being lofty comes from that same imposing verticality.
嶂 combines 山 (mountain) with 章, which likely contributes the sound and may suggest a prominent or marked peak. The exact historical development is uncertain.
The left side is a mountain 山, and the right side 章 looks like a tall, decorated pillar. Picture a mountain so steep it stands like a decorated monument: 嶂 is a lofty, steep peak.
For ショウ, imagine a show being performed on a steep mountain stage: show -> ショウ, and the performers climb the lofty peak to put on the show.