old ceremonial garb, samurai garb, (kokuji)
裃 centers on a specific type of traditional Japanese formal wear: the old ceremonial garb worn by samurai, consisting of a matching upper and lower set (kamishimo).
裃 is a kokuji (a kanji created in Japan) that combines the clothing radical 衤 with a phonetic element 上 (うえ) and 下 (した), reflecting the kamishimo garment's upper and lower parts. The exact historical development of the right-side shape is uncertain, but it likely represents a stylized fusion of 上 and 下.
The left side 衤 (clothing) and the right side looks like 上 (above) and 下 (below) combined. Picture a samurai's ceremonial outfit with a matching upper jacket and lower hakama trousers: 裃 is that formal garb.
For かみしも, break it into かみ (上, upper) and しも (下, lower). Imagine a samurai proudly wearing his kamishimo, pointing to the upper part and saying 'kami' and the lower part 'shimo' — together they make the full reading かみしも.