na-adjective, noun
Describes clothing, appearance, or an occasion that is elegant, formal, or more dressed up than usual. Often used in fashion contexts.
今夜のパーティーはドレッシーな服装でお越しください。
Please come in dressy attire for tonight's party.
このレストランは少しドレッシーな雰囲気だ。
This restaurant has a somewhat dressy atmosphere.