flowing water
湲 centers on the gentle, continuous movement of water: a flowing stream or current. The meaning is narrow and concrete, describing water in motion.
湲 combines the water radical 氵 with the phonetic component 爰, which likely contributed the sound while the water radical indicates the meaning of flowing water.
The water radical 氵 beside 爰 suggests a stream of water moving along. Picture a gentle current flowing past the shape of 爰.
For エン, imagine the flowing water ending in a calm pool: end -> エン, and the water's journey ends there.
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gurgling; babbling; murmuring (stream, brook, etc.)