hood or cowl
襆 centers on a hood or cowl, a garment piece that covers the head, often attached to a cloak or robe.
襆 combines the clothing radical 衤 with the phonetic component 菐, suggesting a garment whose name is related to the sound of 菐. The exact historical development is uncertain.
The left side 衤 is clothing, and the right side 菐 looks like a person with a covering over the head. Imagine a cloak with a hood pulled up: 襆 is a hood or cowl.
For ホク, picture a hawk (ホーク) wearing a tiny hood: hawk -> ホク, and the bird's hood is a 襆.