matted hair
鬙 centers on hair that is tangled, matted, or in disarray. The single given meaning 'matted hair' is the core idea.
鬙 combines 髟 (hair) with 曾, which likely contributes the sound. The character is used for matted or tangled hair.
The top 髟 is the hair radical. Below it, 曾 looks like a tangled mess of strokes. Picture hair so knotted that it forms a dense, matted layer.
For ソウ, imagine a tangled soul (ソウ) of hair that needs combing: soul -> ソウ, and the matted hair is a soulful mess.