noun
genuine article; authentic item; genuine autograph
Used to emphasize that something is the real thing, not a copy or fake. Often appears in contexts like art, antiques, or branded goods. The 'autograph' nuance is specific to signed items.
この絵は正銘のピカソです。
This painting is a genuine Picasso.
正銘のブランド品かどうか見分けるのは難しい。
It's hard to tell whether it's a genuine branded item.
Composed of 正 (correct, genuine) and 銘 (inscription, signature). The combination suggests something bearing a true signature or mark of authenticity.