the virtue of a gentleman, jade
琬 centers on a specific kind of fine jade that symbolizes the virtue of a gentleman—refined, upright, and beautiful. The two given meanings are tightly linked: the stone itself and the moral quality it represents.
琬 combines 王 (jade) with 宛, which likely contributes the sound. The character refers to a fine type of jade and, by extension, the virtue of a gentleman.
The left side 王 (jade) shows this is a precious stone. The right side 宛 looks like a roof over a kneeling person, suggesting something carefully shaped and refined—like a gentleman's polished virtue.
For エン, imagine a gentleman named En polishing a piece of fine jade: En -> エン, and his careful work reflects the stone's virtue.