where could i find this item of clothing

Looks like a suit jacket, to me. You could probably find some at a prom or bridal store? I don't know about many other places. Just...high end formal wear stores is all that comes to mind? Or, if you're lucky and hunt around for one, you could find it at some kind of thrift store.

 

Yeah looks like a regular sport coat. Should be readily available in most men's clothing places.

 

Looks like a blazer to me. You can get pretty cheap ones in h&m or topman. I brought a coat that looks pretty similar from river island recently so that might be another idea. Or if look on eBay/Amazon they'll probably have something similar, just have to hunt for it.

 

Maybe check out Hot Topic and see if they might have something similar? It's like a suit coat or blazer, but more military-esque because of the buttons on the sleeves. Maybe you could get a suit coat and sew similar buttons on.

 

It is a sports jacket or blazer. If you know how to sew you could buy a regular sports jacket/blazer and add the little details yourself.

Since such outfits are common enough in anime you could also check out cosplay sites.

 

You might want to consider checking out Thrift stores while you're at it, you might get lucky.

 

It's a black sports jacket. You could get one Zara man, topman etc. Thrift stores for sure is a good idea. Look for nice materials like wool, tweed and cotton. Avoidtoo much shitty polyester.