wither, droop, lame
凋 centers on decline and loss of vitality: withering, drooping, or becoming weak and lame. It describes something that was once full and strong now fading.
凋 combines 冫 (ice) with 周, which likely contributes the sound. The ice radical suggests coldness and withering, fitting the meaning of decline and drooping.
Ice (冫) surrounds (周) a plant, causing it to wither and droop. The cold makes it lame and lifeless.
For チョウ, imagine a long-serving chief named Chou watching his garden wither in the cold: Chou -> チョウ, and the ice radical makes everything droop.