marketing (= encouraging people to buy a product or service) in such a way that people are not aware that you are trying to persuade them to buy it

Brands have been using stealth marketing for quite some time. 品牌使用隐性营销已经有相当长的一段时间了。

Product placement in films is a form of stealth marketing. 电影中的产品植入是隐性营销的一种形式。