From 夕(ゆう) (yū) + 涼(すず)み (suzumi, “連(れん)用(よう)形(けい) (ren'yōkei, “stem or continuative form”) of the verb 涼(すず)む (suzumu).”).
ゆうすずみ • (yūsuzumi) ←ゆふすずみ (yufusuzumi)?