bathroom, neat, orderly
湢 centers on a clean, well-ordered space, specifically a bathroom. The ideas of neatness and orderliness extend naturally from a room kept tidy and functional.
湢 combines 氵 (water) with 畐, which likely contributes the sound and may relate to fullness or containment. The exact historical development is uncertain, but the character is associated with a water-related room kept orderly.
Water 氵 beside 畐 suggests a room where water is contained and everything is in its place. Picture a bathroom so clean and orderly that even the water flows neatly.
For ヒョク, imagine a bathroom so neat that you could eat a 'hyok' of rice off the floor: the invented sound 'hyok' cues ヒョク while the bathroom stays spotless.