正牌 contrasts with
山寨 (shānzhài, 'knockoff/copycat') and
假冒 (jiǎmào, 'counterfeit'). Beyond products, it's used for credentials (
正牌大学 'an accredited university'), professionals, and even relationships (
正牌女朋友 'official girlfriend' as opposed to a fling or mistress). Casual but pointed.