noun
wearing a yukata; in one's informal summer kimono
Describes the state of being dressed in a yukata, a casual cotton kimono typically worn in summer or at hot springs.
旅館の廊下で浴衣がけの客を見かけた。
I saw a guest in a yukata in the inn's hallway.
浴衣がけで花火大会に行くのが楽しみだ。
I'm looking forward to going to the fireworks festival in a yukata.
浴衣 is the garment itself; 浴衣がけ refers to the state of wearing it.
Compound of 浴衣 (yukata, 'informal cotton kimono') + 掛け (gake, from 掛ける 'to put on, to wear'). The 掛け element indicates the state of wearing.