All I can think of is “investiture”, but that refers to a ceremonial donning of special clothing, not merely, “I’m wearing my new dress for the first time”.
You really need a verb. How about Newbigging?
Unless the item of clothing in question is a new pair of underpants, in which case you might get a touch of Tickford End.
Well, I mostly inaugurate my new stuff, but I’ve heard IT guys put their new Birkenstocks into production, management consultants implement their new Hugo Boss suits, and movie people avant-premiering their new Chuck Taylors. I guess if you were a rocket scientist you might launch your new lab coats, but I don’t know any rocket scientists.
“Show off.” Not in the sense that you’re being a “big showoff,” but rather “to show off for the first time.”
“I’m going to show off my new jeans today.”
“Voy a estrenar mis neuvos jeans hoy.”
That’s Mexican Spanish usage. My English usage almost meshes with etmiller’s Columbian usage, in that “show off” in English isn’t limited to only “for the first time.”
Babelfish tells me the literal translation is “release,” although I’ve never heard it used thus. It’s always used in the sense of “premier,” or with clothing as already discussed.
Odd…Even before Mahaloth gave the Spanish equivalent, I was thinking of the Frech one, which is…étrenner.
I checked in two English-French dictionaries, and both give
“to use/wear for the first time”
So there doesn’t seem to be one word in English to render this meaning.
I can’t ever remember hearing the word in actual use, but I was taught that “estrenar” means, sort of, “to debut”. According to my teacher, it doesn’t have to refer to clothing necessarily (though it may be that this is one of the most typical uses of the word - her examples did specifically have to do with her clothing.)