noun
first wear; first use of new clothes
Refers to wearing a newly purchased or made garment for the first time. Often used in the context of special occasions or seasonal items.
See also: 下ろし (おろし)
今日は新しいスーツの初おろしだ。
Today is the first time I'm wearing my new suit.
初おろしの着物でお茶会に行く。
I'm going to a tea ceremony in a kimono I'm wearing for the first time.
下ろす means to take down or to launch; 初おろし is the noun form for the first use of something, especially clothing.
Compound of 初 (hatsu, 'first') and 下ろし (oroshi, from 下ろす, 'to take down' or 'to use for the first time'). The exact historical derivation is uncertain, but it refers to the first time an item is taken out and used.